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COLUMBIA    UNIVERSITY 
DEPARTMENT     OF     PHYSIOLOGY 
THE    JOHN    G.   CURTIS    LIBRARY 


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Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 

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m^STERS    OF    ,^EDICI3\CE 


mOMINES  AD  DEOS  NULLA  IN  UE  r 
liPROPIUS  XCCEDUNT  QUXM  ^ 
SALUTEM  HOMINIBUS    DANDOV 

-    - CICERO. 


Masters  of  Medicine 


Title. 

John  Hunter 
William  Harvey 
Sir  James  Y.  Simpson  . 
William  Stokes  . 
Sir  Benjamin  Brodie 
Claude  Bernard 
Hermann  von  Helmholtz  . 
Andreas  Vesalius 
Thomas  Sydenham 


Author. 
Stephen  Paget 
D"* Arcy  Power 
H.  Laing  Gordon 
Sir  TVilliam  Stokes 
Timothy  Holmes 
Michael  Foster 
John  G.  McKendrick 
C.  Louis  Taylor 
y,  F.  Payne 


M 


A5TERS 

OF 
EDICINE 


CLAUDE   BERNARD 


r^ 


Claude  Bernard 


BY 


Michael  Foster,  M.A.,  M.D., 
D.C.L.,  Etc. 

Secretary  of  the  Royal  Society  of  London 

PROFESSOR    OF    PHYSIOLOGY    IN    THE    UNIVERSITY    OF 
CAMBRIDGE 


l4f^C9J 


(MiEW  YORK 

LONGMANS,   GREEN  &  CO. 

91    &   93,   FIFTH   AVENUE 
1899 


T^So<\'.S.vs" 


SDetiication. 


TO   THE   PHYSIOLOGISTS    OF    FRANCE, 

BOTH    TO    TH05E    WHO      HAD     THE     HAPPI-\E55    TO     KNOW 

CLAUDE  BERNARD  IN  THE   FLESH,  AND  TO  THOSE  WHO, 

LIKE  MYSELF,  NEVER  SAW   HIS    FACE,  THIS  LITTLE 

SKETCH    15    DEDICATED    IN    THE    HOPE    THAT 

AS   HE   HAS    BEEN   TO    ME    A    FATHER    IxV 

OUR  COMMON  SCIENCE,    SO   I    MAY 

BE    ALLOWED   TO    LOOK    UPON 

THEM     AS     BRETHREN. 

M.    FOSTER. 


Vll 


PREFACE 

OOME  may  think  that  in  the  pages 
which  follow  too  much  space  is  given 
to  an  exposition  of  Claude  Bernard's 
scientific  work  and  too  little  to  the  details 
of  his  life  as  a  man.  Although  the  real 
life  of  every  great  man  of  science  lies  in 
the  story  of  his  scientific  work  and  not 
in  the  tale  of  how  he  passed  his  days,  we 
all  of  us  wish  to  clothe  the  image  which 
we  have  formed  of  a  man  whom  we  know 
by  his  writings  only,  with  as  many  details 
as  we  can  gather,  of  how  he  moved  among 
his   fellow-men,  and  what  befell  him  on 


IX 


PREFACE 

his  path  through  life.  And  had  I  been 
able  to  do  so,  I  would  have  added  much 
to  what  I  have  written.  But  the  details 
which  can  now  be  gained  of  Bernard's 
daily  life  are  very  scanty.  I  can  only 
say  that  I  have  done  my  best  ;  and  the 
little  which  I  have  been  able  to  do  has 
been  made  possible  by  the  kindness  of 
my  friends,  especially  of  Prof.  A.  Dastre, 
who  now  holds  Bernard's  chair  at  the 
Sor bonne  ;  of  Prof.  C.  Richet,  of  the  Ecole 
de  Medecine ;  and  of  Prof.  W.  Kiihne,  of 
Heidelberg,  who  was  once  Bernard's  pupil. 

Cambridge, 
May  3,  1899. 


CONTENTS 


'¥ 


I.      Early  Days 


PAGE 
I 


II.     The  Condition  of  Physiological 
Science  before  Bernard  began 


HIS  Labours 

.      22 

III. 

Early  Labours    . 

•    43 

IV. 

Glycogen      .         . 

.    6i 

V. 

Vaso-Motor  Nerves     . 

.    100 

VI. 

Other  Discoveries 

.  135 

VII. 

His  Later  Writings  . 

.  160 

VIII. 

Later  Years 

.  198 

IX. 

Conclusion    .         .         .         , 

.  226 

Index     .         .         . 

•  239 

XI 


CLAUDE    BERNARD 


Early  Days 

THE  traveller  speeding  southwards  by 
the  Paris,  Lyons  and  Mediterranean 
express,  some  little  time  before  he  reaches 
Lyons  rushes  through  the  station  belong- 
ing to  the  town  of  Villefranche.  Not  far 
from  that  town — two  or  three  leagues 
distant — lies  the  little  village  of  Saint- 
Julien  (Rhone),  in  which  on  July  12, 
1 8 13,  Claude  Bernard  was  born.  His 
father  was,  in  common  with  most  of  his 
neighbours,  the    humble  proprietor   of   a 


CLAUDE   BERNARD 

small  estate  chiefly  planted  with  vines,  and 
derived  at  least  most  of  his  income  from 
making  wine.  The  whole  district  was, 
and  indeed  still  is,  a  wine-producing  land  ; 
it  is  part  of  the  old  province  of  Beaujolais, 
and  the  wine  which  it  yields  bears  that 
name. 

The  little  estate  eventually  came  into 
Bernard's  hands,  and  so  soon  as  he  could 
afford  it,  or  at  least  in  his  later  years,  he 
used  the  paternal  cottage  as  a  summer 
residence  during  the  vacations.  Here  he 
yearly  renewed  his  strength  by  touch  with 
his  native  earth,  exchanging  Paris  for  the 
simplicities  of  country  life,  and  mingling 
quiet  literary  labours  with  the  amusement 
of  watching  the  vintage  of  his  own  wine. 
He  thus  himself  describes  his  home  : 

"  My  dwelling  is  on  the  hill  slopes  of 
Beaujolais  which  look  towards  the  Dombe. 
The  Alps  give  me  my  horizon  and  when 

2 


EARLY   DAYS 

the  air  is  clear  I  can  catch  sight  of  their 
white  summits.  At  the  same  time  I  see 
spread  out  before  me  for  two  leagues  the 
prairies  of  the  Saone.  The  slope  on 
which  I  dwell  is  surrounded  on  all  sides 
by  vineyards  stretching  away  apparently 
without  limit  ;  these  would  give  the 
country  a  monotonous  appearance  were 
not  this  broken  by  wooded  valleys  and 
brooks  running  down  from  the  mountains 
to  the  river.  My  cottage,  situated  though 
it  is  on  a  rise,  is  a  very  nest  of  verdure, 
thanks  to  a  little  wood  which  shades  it  on 
the  right  and  to  an  orchard  v/hich  flanks 
it  on  the  left ;  a  great  rarity  in  a  land  in 
which  they  stub  up  even  the  coppices  in 
order  to  plant  vines." 

In  this  quiet,  out-of-the-way  spot,  the 
future  physiologist  began  life  as  a  member 
of  a  homely  family,  whose  aspirations 
scarcely  went  beyond  securing  their  daily 

3 


CLAUDE    BERNARD 

bread.  As  a  child  he  must  have  been 
bright,  for  the  cure  took  him  under  his 
special  charge,  making  him  a  choir  boy 
and  teaching  him  Latin.  He  afterwards 
was  sent  to  the  school  or  so-called  college 
at  Villefranche,  directed  by  the  Jesuits. 

When  he  had  learnt  as  much  as  his 
teachers  could  teach  him  at  the  college, 
he  was  sent  to  Lyons,  with  the  view 
probably,  in  the  first  instance,  of  his 
completing  his  studies  and  obtaining  the 
Baccalaureat.  But  his  student  career  at 
Lyons  could  not  have  been  a  very 
lengthy  one,  for  he  soon  entered  into 
active  life,  exchanging  the  school  for  the 
shop.  The  reasons  which  led  to  this 
step  cannot  be  ascertained,  but  they 
do  seem  to  have  been  financial.  The 
family,  though  humble,  were  not  with- 
out resources.  Claude  appears  to  have 
been  an   only  son,  with    one    sister,  who 

4 


EARLY   DAYS 

eventually    married    a  neighbouring    pro- 
prietor.    The  father   seems  to  have  been 
still  aUve   (though  he  is  said  to  have  died 
while    Bernard    was    yet   young)   and  not 
yet  to  have  met  with  the  reverses  which 
subsequently  crippled  the  family.     Be  it  as 
it  may,  Bernard,  somewhere  in  his  teens, 
became    engaged   at    Lyons    in    practical 
pharmacy,    having    obtained    a    situation 
with    a    pharmacist    in    the    Faubourg   de 
Vaise  of  that  city.      He  received  at  first 
nothing  more   than  his   board  and  lodg- 
ing for  his  services  in   the  shop,  though 
after  some  months,  his  manual  dexterity, 
shown  by  the  singular  neatness  of  his  "  dis- 
pensing," was  rewarded  by  a  humble  salary. 
Here  for  some  time,  probably  for  two 
years,  Bernard  spent  most  of  his  days  as  a 
pharmaceutical  assistant,  dispensing    medi- 
cines, and    carrying  them  to    the   clients, 
especially  to  the  Veterinary  School.     What 

5 


CLAUDE   BERNARD 

opportunities  for  pharmaceutical  study  he 
had  does  not  appear  ;  but  his  patron's 
mode  of  conducting  his  business  served  to 
awake  in  him  early  the  spirit  of  medical 
scepticism.  As  was  usual  at  that  epoch 
the  clients  of  the  shop,  especially  the  old 
women  of  the  outlying  villages,  made  a 
constant  demand  for  a  syrup  which  seemed 
to  cure  everything  ;  and  Bernard,  to  his 
astonishment,  found  that  this  favourite 
syrup  was  compounded  of  all  the  spoilt 
drugs  and  remnants  of  the  shop.  When- 
ever Bernard  reported  that  a  bottle  of 
stuff  had  gone  wrong,  "  Keep  that  for 
syrup,"  replied  the  master ;  ''  that  will 
do  for  making  the  syrup." 

No  wonder  that  Bernard's  mind  turned 
with  avidity  to  other  things  than  pharmacy. 
In  common  with  many  of  the  young  men 
of  his  time,  he  was  filled  with  literary 
aspirations  ;  and  he  was  particularly  drawn 

6 


EARLY   DAYS 

towards  the  dramatic  art.  All  his  free 
evenings  he  spent  at  the  play,  at  the  Theatre 
des  Celestins,  and  was  moved  to  write 
himself  a  vaudeville  comedy,  entitled  "La 
Rose  du  Rhone,"  which  was  not  only 
accepted,  but  had  a  certain  success  on  the 
boards,  though  it  was  never  printed. 

Encouraged  by  the  result  of  this  first 
effort,  he  set  himself  to  the  serious  work 
of  writing  a  historic  piece  in  the  con- 
ventional five  acts,  giving  it  at  first  the 
form  of  a  tragedy  in  metre,  but  sub- 
sequently changing  it  to  a  prose  drama. 
With  this  he  determined  to  seek  his 
fortune  in  Paris.  He  had  in  Lyons  two 
friends,  like  himself,  students  and  poor. 
All  three  thought  that  Lyons  was  too  small 
a  sphere  for  their  abilities,  all  three  deter- 
mined that  the  proper  place  for  them  was 
Paris.  They  parted  from  each  other  at 
Lyons,  giving  each  other  the  rendezvous 


CLAUDE   BERNARD 

in  Paris,  or  as  they  called  it,  "  la  scene  du 
Monde."  And  Bernard  used  to  tell  after- 
wards, in  a  joking  spirit,  how  by  chance 
they  did  later  on  meet  together  in  the 
Place  du  Pantheon,  in  front  of  the  well- 
known  inscription  *'  Aux  grands  Hommes 
la  Patrie  reconnaissante  "  !  And  though 
the  omen  did  not  hold  so  good  for  the  other 
two  as  it  did  for  Bernard,  yet  one  became 
a  Bishop,  and  the  other  a  Director  of 
Railways. 

Bernard,  with  the  help  of  the  few  francs 
which  his  little  comedy  had  put  in  his 
pocket,  started  in  the  diligence  for  Paris, 
armed  with  his  manuscript  of  "  Arthur  de 
Bretagne,"  carefully  rolled  up,  and  with  a 
letter  of  introduction  to  the  great  critic 
Saint-Marc  Girardin,  which  a  professor  in 
the  Faculty  of  Letters  at  Lyons  had  given 
him.  It  was  in  1834,  and  he  was  just 
about  one  and  twenty  years  old. 

8 


EARLY   DAYS 

Girardin,  then  Professor  at  the  Sor- 
bonne,  received  the  young  student  kindly, 
and  conscientiously  read  his  manuscript. 
He  saw  (as  indeed  one  may  see  now,  for 
the  drama  was  published  in  a  fine  edition 
after  Bernard's  death  in  1886,  by  the 
Librairie  Dentu  of  Paris),  that  the  drama 
showed  that  the  author  possessed  literary 
powers  of  no  mean  kind  ;  but  he  shrank 
from  giving  to  the  aspirant  the  hopes 
which  might  have  been  his  due.  Instead 
of  encouraging  him  to  devote  himself  to 
literature  he  bade  him  turn  to  something 
else  by  which  to  earn  his  bread,  and  court 
the  Muses  in  his  leisure  moments  only. 
"Y'ou  have  studied  pharmacy,"  said  he; 
"study  medicine,  you  will  thereby  much 
more  surely  gain   a  livelihood." 

Bernard  followed  the  advice,  and  threw 
himself  heart  and  soul  into  medical  studies, 
living   in   the    most   frugal    manner,    sup- 

9 


CLAUDE   BERNARD 

porting  himself  and  paying  the  necessary- 
fees  chiefly  with  the  scant  money  which  he 
earned  by  giving  lessons  ;  for  his  family 
could  spare  him  very  little  help,  at  most 
some  trifling  sums  of  money  and  an  occa- 
sional hamper  of  country  produce.  More- 
over his  father  died  about  this  time, 
having  met  with  reverses  before  his  death. 
But  a  student's  life  in  the  Quartier  Latin, 
at  that  time  at  all  events,  was  not  a  costly 
affair.  A  garret,  shared  perhaps  by  a 
comrade,  served  as  bedroom  and  study, 
and  at  times  as  kitchen,  for  when  a  gift 
came  from  the  country  home  it  was  cooked 
and  eaten  in  the  *'  appartement,"  with  the 
help  of  utensils  impressed  or  borrowed 
from  the  laboratory. 

Bernard  worked  hard  at  all  his  medical 
studies,  and  in  the  tumult  of  the  new  ideas 
crowding  in  upon  him  his  old  literary 
aspirations  soon  grew  faint  and  vanished. 

10 


EARLY    DAYS 

Most  especially  did  he  devote  himself  to 
anatomy  and  physiology.  In  the  former 
he  recognised  a  branch  of  science,  limited 
it  is  true  in  range,  but  one  which  had  been 
studied  with  such  rigour  and  exactitude  as 
to  have  become  a  mental  discipline  of  no 
mean  value.  He  soon  made  himself 
master  of  the  subject,  acquiring  a  know- 
ledge of  it  at  once  extensive  and  minute, 
while  his  conspicuous  manual  dexterity  led 
to  the  dissections  which  he  made  being 
regarded  by  others  as  anatomical  pre- 
parations of  singular  completeness  and 
value.  Moreover,  he  seems  in  these  early 
days  to  have  looked  forward  to  the  career 
of  a  surgeon  as  the  one  by  which  he  might 
hope  to  gain  a  livelihood  ;  and  to  such  a 
career  anatomy  was  the  most  direct  path. 
Physiology  was  at  that  timie  in  a  very 
different  condition  from  anatomy  ;  in 
place  of  light  there  v/as  for  the  most  part 

II 


CLAUDE   BERNARD 

darkness,  and  in  place  of  clear  and  distinct 
guidance,  uncertainty  and  dubious  discus-- 
sion.  What  Bernard  thought  of  the  most 
of  the  teaching  of  physiology  of  the  time, 
we  can  gather  from  his  utterances  later 
on  ;  and  we  can  confidently  suppose 
that  even  in  his  early  days  he  clearly 
distinguished  between  the  science  as  it  was 
taught  and  the  science  as  it  ought  to  be 
taught.  If  anatomy  served  to  supply  his 
intellectual  appetite  for  exact  and  minute 
knowledge  in  the  shape  of  concrete  facts, 
physiology  served  to  awaken  in  his  mind 
the  desire  to  solve  problems  by  a  direct 
experimental  appeal  to  nature.  He  lived 
as  a  student  in  the  Quartier  Latin  in  a 
little  "  entresol "  in  the  old  *'  Passage  du 
Commerce  Saint  Andre  des  Arts,"  not 
far  from  the  spot  where  Marat  printed 
"  L'Ami  du  Peuple,"  from  the  house  in 
which  Danton  lived,  and  from  that  in  which 

12 


EARLY    DAYS 

Guillotin    tried   the    value    of  his    famous 
invention    on    the    necks    of    sheep.      In 
that    little    apartment    he    made    his    first 
attempts  at  experiments  on  living  animals. 
A  little  later  on  he,  in  partnership  with  a 
fellow  student,  Lasegue,  opened  a  humble 
experimental    laboratory   in  the   old    Rue 
Saint-Jacques,     nearly    opposite    the    Col- 
lege de  France,  his  purpose   in    doing  so 
being,    apparently,    partly    to    gain    some 
money  by  fees,  but   partly,   and    perhaps 
chiefly,  to  obtain    ampler  and  more   con- 
venient means   for   carrying   on  his   own 
budding  researches.      Alas,    the  enterprise 
was    not     successful.      Only    some    half- 
dozen  students  availed   themselves  of  the 
opportunity    offered.       The     fees     never 
brought  enough  to   pay  the  rent  and  the 
cost  of  the  rabbits  employed,  and  the  little 
laboratory  was  soon  closed. 

Nor   in   his    more   strictly   professional 

13 


CLAUDE   BERNARD 

efforts  did  Bernard  at  first  attract  atten- 
tion. Retiring,  thoughtful,  with  his 
mind  already  bent  on  problems  to  be 
solved,  awkward  in  manner,  and  wholly 
removed  from  the  desire  so  common  to 
others  to  appear  better  than  he  really  was, 
he  did  not  impress  either  his  comrades  or 
the  authorities  with  his  power. 

To  the  former,  indeed,  except  in  the 
dissecting-room,  he  appeared  somewhat  idle 
and  inattentive.  They  were  for  the  most 
part  unable  to  criticise  their  teachers. 
Their  intellectual  activity  was  chiefly 
receptive  ;  it  rarely  went  beyond  the  task 
of  carefully  listening  to  the  words  which 
fell  from  the  professorial  chair,  and 
treasuring  them  in  their  memories  to  be 
reproduced  at  .the  appointed  time  in  the 
examination  room.  He,  on  the  contrary, 
seems  to  have  begun  early  to  ponder  over 
the  questions  which  were  treated  of  in  the 

14 


EARLY   DAYS 

lectures  ;  he  soon  detected  flaws  in  his 
teachers'  reasoning,  and  thus  speedily 
beginning  to  doubt  the  value  of  the 
teaching,  paid  but  a  listless  attention  to 
expositions  and  discussions,  the  weakness 
of  which  became  more  and  more  clear  to 
him  as  time  went  on.  Such  a  spirit, 
though  it  may  bear  admirable  fruit  in  the 
end,  is  not  very  profitable  at  the  schools. 
Possibly,  moreover,  the  young  student, 
quiet  and  reserved  as  he  seemed,  had 
within  him  not  a  little  intellectual  pride, 
which  tempted  him  to  neglect  beyond 
measure  instruction  which  seemed  to  him 
of  dubious  value.  Though  in  his  exami- 
nations and  otherwise  he  showed  himself 
to  be  an  able  student,  neither  to  his 
fellow  students  nor  to  his  teachers  did 
he  seem  one  who  was  about  to  make 
a  great  mark. 

In  the  fifth  year  of  his  studies,  however, 
15 


CLAUDE    BERNARD 

his  opportunity  came  to  him.  After 
serving  as  usual  as  "  externe  "  at  the  Hos- 
pitals he  was  in  1839  appointed  "interne"; 
and  Providence  ruled  that  he  should  be 
allotted  to  Magendie,  who  was  then  one  of 
the  Physicians  to  the  Hotel  Dieu. 

Magendie,  then  the  leading  physiologist 
in  France,  held  two  offices.  He  was 
Physician  to  the  Hotel  Dieu,  and  Pro- 
fessor of  Medicine  at  the  College  de  France. 

The  latter  famous  institution  was  founded 
by  Francis  I.  in  1530,  the  year  after  the 
Treaty  of  Cambray,  under  the  name  of  the 
College  Royal  or  College  des  trots  langues,  the 
first  chairs  established  being  those  of  Greek, 
Hebrew,  and  Latin.  It  was  founded  as  a 
place  of  free  learning  with  the  desire  to 
antagonise  the  more  rigid  and  scholastic 
teaching  of  the  University  in  the  Sorbonne. 
The  Royal  Readers  or  Professors  paid 
directly  by  the  King  were  free  to  teach  as 

16 


EARLY   DAYS 

they  pleased  within  the  subjects  defined  by 
their  titles.  The  lectures  were  open  to  all 
without  fees,  and  the  whole  object  of  the 
foundation  was  to  encourage  liberal  and 
higher  learning.  At  first  the  College  had 
no  fixed  abode,  the  Professors  delivering 
their  lectures  where  they  could  ;  indeed  it 
was  not  until  loiothat  Louis  XIIL,  carry- 
ing out  the  promise  made  by  Henry  IV., 
began  the  construction  of  a  building  which, 
however,  through  various  delays,  was  not 
completed  and  hence  not  used  until 
1636. 

To  the  chairs  of  the  three  tongues, 
Francis  L  added  those  of  mathematics, 
philosophy,  and  medicine,  the  first  holder 
of  that  of  medicine  being  the  Florentine 
Guido  Guidi,  known  as  Vidus  Vidius,  who 
entered  into  the  post  in  1542.  He  was 
succeeded  in  1550  by  the  great  anatomist 
Jacques  du  Bois,  better  known  by  his  Latin 

17  c 


CLAUDE   BERNARD 

name  of  Jacobus  Sylvius,  one  Beauvais 
intervening  for  three  years. 

Various  other  chairs  were  subsequently 
founded,  and  in  the  course  of  time 
numerous  changes  took  place.  Charles 
IX.  founded  in  1568  a  chair  of  medicine, 
Henry  III.  founded  one  of  surgery  in 
1575,  and  Henry  IV.  in  1595  one  of 
anatomy,  botany,  and  pharmacy,  the 
second  holder  of  which  was  Jean  Riolan. 
By  1680,  all  these  four  chairs  had  come 
to  be  all  equally  devoted  to  medicine, 
surgery,  botany,  and  pharmacy. 

Towards  the  close  of  the  eighteenth 
century,  however,  great  changes  were  made. 
The  first  chair  of  medicine  became  a  chair 
of  chemistry,  held  from  1865  onwards 
by  the  present  eminent  chemist  Berthelot. 
The  second  chair  of  medicine  became  a 
chair  of  Natural  History  held  by  the 
illustrious    Cuvier    from    1799    to    1832. 

18 


EARLY   DAYS 

And    the    chair    of    surgery    became    the 
one    chair    of    Medicine    held    for    some 
years  by  Laennec,  and  filled  at  the  time 
of  which  we  are  speaking  by  Magendie. 
During    all    these  years,    however,    the 

* 

principle  of  the  College  remained  the  same. 
The  professors  were  at  liberty  to  lecture 
without  the  restraints  of  a  syllabus  having 
an  examination  as  its  goal,  the  lectures 
were  free  to  all  who  wished  to  hear, 
and  the  general  idea  that  the  place  was 
devoted  to  higher  study  still  maintained 
its  sway. 

Following  the  old  tradition,  it  continued 
to  be  recognised  that  the  duty  of  a  Professor 
holding  a  chair  in  the  College  was  not  to 
give  didactic  lectures  suitable  to  an  ordinary 
student,  but  rather  to  use  the  post  as  an 
instrument  of  research,  and  to  expound 
new  ideas  to  those  who  were  already 
advanced    in    their    studies.      Thus,    for 

19 


CLAUDE   BERNARD 

example,  the  lectures  which  Magendie 
delivered  there  in  1838-40  were  afterwards 
published  in  the  well-known  work,  "  Phe- 
nomenes  Physiques  de  la  Vie."  Carrying 
out  the  idea  of  research,  there  was  allotted 
to  the  Professor  of  Medicine  in  a  lower 
story  of  the  building  accommodation  for 
research  in  the  form  of  a  dark  unwholesome 
room  called  a  laboratory.  There  was  also 
provided  for  the  Professor  a  frefarateur 
to  assist  him  in  the  experiments  with 
which  he  illustrated  his  lectures,  or  in 
those  connected  with  his  researches. 

Bernard's  first  contact  with  Magendie 
was  not  promising.  The  professor,  in  the 
ward  and  in  the  laboratory  at  least,  was 
in  manner  abrupt,  even  rough  and  rude. 
He  took  little  notice  of  his  new  interne^ 
hardly  even  asking  his  name.  After  not 
many  days,  however,  the  conspicuously 
skilful  way  in  which  Bernard  carried  out 

20 


EARLY   DAYS 

the  dissections  which  were  entrusted  to 
him  made  a  very  marked  impression  on  his 
master  ;  and  the  story  goes  that  one  day, 
early  in  their  intercourse,  Magendie,  on  a 
sudden,  called  out  roughly  to  Bernard,  busy 
at  a  dissection,  ''  I  say,  you  there,  I  take 
you  as  my  preparateur  at  the  College  de 
France."  Bernard  was  only  too  glad  to 
accept  the  offer.  There  is  some  doubt  as 
to  whether  he  was  not,  during  the  first 
year,  a  mere  voluntary  assistant,  but  in 
any  case,  in  1841  he  had  become  the 
official  preparateur.  Bernard's  career  as  a 
physiologist  may  be  said  to  date  from 
then.  Before  proceeding  any  further, 
however,  it  will  be  desirable  to  form  some 
idea  of  the  state  of  physiology  in  Europe 
in  general,  and  in  France  in  particular  at 
this  epoch. 


21 


II 

The   Condition   of    Physiological  Science 
BEFORE  Bernard  began  his  Labours 

WHEN  the  physiologist  to-day, 
knowing  how  dominant  has  been 
the  influence  of  Germany  on  physiology 
in  the  present  century,  inquires  what  was 
the  condition  of  physiology  in  Germany 
in  about  the  year  1840,  when  Bernard 
joined  Magendie,  he  is  at  once  struck  with 
the  fact  that  the  great  German  physiologists 
of  the  present  century,  Ludwig,  Helm- 
holtz,  du  Bois-Reymond,  and  Briicke, 
had  at  that  time  not  commenced  their 
labours.     All  the  great  work  which  these 

22 


PHYSIOLOGICAL   SCIENCE 

have  done  was  done  after  that  date  ;  their 
labours  were  contemporaneous  with  those 
of  Bernard.  The  dominant  physiological 
mind  in  Germany  at  that  time  was  that  of 
Johannes  Miiller.  That  great  man  had  in 
his  earlier  years  devoted  much  time  to 
definite  physiological  inquiry,  especially 
into  problems  relating  to  the  senses  ;  he 
was  a  great  teacher  of  physiology,  inspiring 
a  love  for  the  science  and  a  true  spirit  of 
inquiry  into  it  among  his  numerous  pupils  ; 
and  he  had  written  a  masterly  text  book, 
his  "  Outlines  of  Physiology,"  the  influence 
of  which  not  only  on  his  own  countrymen 
but  on  others  has  been  profound. 

Johannes  Miiller  has  been  called  a 
*'  vitalist,"  and  in  a  certain  sense  he  v/as 
one.  In  his  '*  Outlines  "  he  criticises  the 
views  of  Reil  "  that  the  phenomena  of  life 
are  the  result,  manifestation,  or  property 
of  a  certain  combination  of  elements,"  and 

23 


CLAUDE   BERNARD 

contends  for  the  necessity  of  supposing  the 
existence  of  an  "organic  or  vital  principle 
or  force,"  "  the  action  of  which,  however, 
is  not  independent  of  certain  conditions." 
In  judging  Johannes  Miiller's  scientific 
attitude,  it  must  be  remembered  that 
though  a  physiologist  he  was  also  a  morpho- 
logist,  and  indeed,  on  the  whole,  more  the 
latter  than  the  former  ;  hence  the  organic 
principle  was  of  more  importance  to  him 
as  a  something  determining  the  form  of 
living  beings  than  as  an  explanation  of 
the  phenomena  presented  by  their  activity. 
Moreover  he  was  not  a  vitalist  in  the  sense 
that  he  discouraged  attempts  to  solve  the 
problems  offered  by  the  actions  of  living 
beings  by  experiments  based  on  the  view 
that  these  were  the  outcome  of  physico- 
chemical  agencies,  or  that  he  refused  to 
admit  a  physico-chemical  explanation  when 
this  could  be  shown  to  be  adequately  valid. 

24 


PHYSIOLOGICAL   SCIENCE 

He  was  a  vitalist  only  in  the  sense  that  he 
was  theoretically  of  opinion  that  even  when 
the  physico-chemical  analysis  of  vital  phe- 
nomena had  been  pushed  as  far  as  it  could, 
there  would  still  remain  a  large  residue 
which  could  not  be  explained  through  any 
such  analysis  however  complete.  And 
indeed  the  fact  that  his  pupils,  the  great 
men  mentioned  above,  were  conspicuous 
by  their  efforts  to  solve  physiological  pro- 
blems by  such  a  chemico-physical  analysis, 
shows  clearly  how  much  the  master's 
vitalism,  so  far  as  physiology  was  con- 
cerned, was  academic  in  nature,  and  that 
his  influence  as  a  teacher  vv^as  strongly  in 
the  direction  of  guiding  the  physiologist 
to  attack  his  problems,  by  the  same 
methods,  and  in  the  same  spirit,  that  the 
chemist   or  the   physicist  attacked  his. 

The    teaching    and    influence     in     the 
same  direction  of  another  gr^at    man,  E. 

25 


CLAUDE   BERNARD 

H.  Weber,  was  even  more  decided  and 
clear  ;  for  he  by  the  bent  of  his  mind, 
no  less  than  by  fraternal  ties,  was 
not  only  a  physiologist,  but  also  a 
physicist. 

The  other  strong  men  in  Germany 
were  also  teaching  and  practising  the  same 
view.  It  is  only  necessary  to  mention  the 
names  of  Henle,  who  though  in  the  main 
an  anatomist,  was  ever  in  search  of 
physiological  light,  of  Tiedemann,  of 
Volkmann,  of  Vierordt,  and  of  Bidder, 
to  say  nothing  of  the  earlier  labours 
of  Theodore  Schwann.  The  mark  of  all 
these  was  that  they  set  about  the  solution 
of  physiological  problems  in  the  same  spirit 
in  which  the  physicist  or  chemist  sets  about 
his  ;  to  them  the  canons  of  scientific  in- 
quiry were  the  same  for  living  as  for  non- 
living phenomena  ;  they  only  had  recourse, 
and    then    with     reluctance,    to    vitalistic 

26 


PHYSIOLOGICAL   SCIENCE 

explanations  when  their  means  of  analysis 
proved  impotent. 

On  the  whole  the  dominant  spirit  of 
physiological  inquiry  in  Germany  was  at 
that  time  very  much-  what  it  is  now.  The 
contrast  between  to-day  and  then  lies  chiefly 
in  the  paucity  of  opportunity  for,  and  in 
the  scarcity  of  men  engaged  in,  experi- 
mental inquiry.  Physiological  laboratories, 
such  as  abound  now,  were  then  alm.ost 
unknown.  But  in  this  respect  physiology 
was  hardly  in  a  worse  condition  than  the 
other  experimental  sciences.  Until  Liebig 
began  his  career  at  Giessen,  chemical 
laboratories  as  we  now  know  them  did  not 
exist,  and  physical  laboratories  were  a  still 
later  creation.  Such  things  do  not  come 
until  a  call  has  been  made  for  them.  The 
call  was  being  made  for  them  and  they  soon 
came.  The  time  at  which  Bernard  began 
his  work  at  Paris,  was  also  the  time  for  an 

27 


CLAUDE    BERNARD 

independent  development  in  Germany  of 
opportunities  for,  and  of  the  prosecution  of, 
physiological  research  ;  it  was  then  that 
Ludwig  and  the  other  great  German 
physiologists  began  their  active  careers. 

In  England  the  pursuit  of  physiology  as 
a  distinct  science  had  but  few  followers,  but 
these  for  the  most  part  were  treading  the 
experimental  path.  The  energetic  exposi- 
tions by  Marshall  Hall  of  the  reflex  actions 
of  the  nervous  system,  following  up  and 
extending  as  they  did  the  earlier  leadings 
of  Charles  Bell,  were  showing  that  this  part 
of  physiology,  apparently  the  farthest 
removed  from  the  sciences  of  inorganic 
nature,  might  be  successfully  studied  by 
the  same  experimental  methods. 

John  Reid,  by  his  researches  on  the 
cranial  nerves,  was  working  in  a  more 
special  and  narrower  way  towards  the 
same  end.      The    sagacious    Sharpey    was 

28 


PHYSIOLOGICAL   SCIENCE 

teaching  and  was  encouraging  research  in 
a  spirit  identical  with  that  which  governs 
physiological  inquiry  at  the  present  day. 
And  in  the  very  year  1840,  up  to  which 
we  have  so  far  traced  Bernard's  life, 
William  Bowman  made  known  to  the 
world  the  results  of  those  inquiries  into 
the  structure  of  muscle,  and  was  about 
soon  to  make  known  the  results  of  those 
other  inquiries  into  the  structure  of  the 
kidney,  which  still  remain  and  will  always 
remain  models  of  histological  research  so 
directed  as  to  throw  light  on  physiological 
problems.  One  man  only  of  mark,  John 
Goodsir,  and  he  more  a  morphologist  than 
a  physiologist,  was  teaching  views  in  which 
a  mystical  tendency  tempted  the  mind 
away  from  the  more  commonplace  paths 
of  simple  observation  and  experiment. 

In  Italy,  pressed  down  as  she  was  at  the 
time  by  political  difficulties,  and  bound  by 

29 


CLAUDE    BERNARD 

ecclesiastical  bonds,  even  less  was  being 
done,  though,  somewhat  earlier,  Spallanzani 
and  Fontana  had  shown  what  could  be 
achieved  amid  such  adverse  influences. 
Matteuci  and  others  were,  it  is  true, 
carrying  out  valuable  researches  on  ordinary 
lines ;  but  no  prominent  mind  was  distinctly 
influencing  general  physiological  thought. 

Turning  now  to  France  itself  v/e  find  a 
somewhat  different  condition  of  things.  In 
that  country,  perhaps,  even  more  than  in 
other  countries,  patriotism  has  a  tendency 
to  manifest  itself  by  a  too  exclusive  atten- 
tion to  views  put  forward  by  native  writers  ; 
and  this  was  in  some  ways  especially  the 
case  at  the  epoch  with  which  we  are  dealing. 
The  influences  v/hich,  as  we  have  just  said, 
were  becoming  potent  as  regards  physiolo- 
gical inquiry  in  Germany,  and  were  also 
producing  a  marked  effect  in  England, 
were,   it    would    seem,    felt    but   little    in 

30 


PHYSIOLOGICAL   SCIENCE 

France.  The  Frenchman  who  dealt  with 
physiological  questions  was  in  the  main 
influenced  by  his  predecessors  in  his  own 
land.  And  at  that  time  the  teachings  of 
two  men  were  in  different  ways  especially 
powerful.  The  influence  of  the  great 
Cuvier,  who  had  mastered  not  only  his 
subject  but  his  opponents,  was  at  that 
time  supreme.  He,  like  other  mor- 
phologists,  impressed  with  the  impotence 
of  the  mechanical  explanations  offered  as 
solutions  of  morphological  problems,  was 
led  to  depreciate,  in  like  manner,  any 
physico-chemical  explanation  offered  as  a 
solution  of  a  physiological  problem,  and  so 
became  an  ardent  supporter  of  vitalistic 
views.  His  influence  was,  so  to  speak, 
from  the  outside  ;  yet  it  was  a  living 
influence  and  had  only  ceased  to  be  such 
a  few  years  before.  Within  the  science  of 
physiology  itself  the  influence  of   Bichat, 

3^ 


CLAUDE    BERNARD 

though  it  was  that  of  a  man  who  had  long 
passed  away,  was  exceedingly  powerful. 
Bichat  had  laid  hold  of  a  great  idea,  one 
which  rapidly  spread  from  the  land  in 
which  it  was  first  expounded  to  other 
lands,  and  has  in  a  most  marked  way 
helped  to  make  physiology  an  exact 
science,  the  idea  that  the  life  of  the  body 
is  the  outcome  of  the  combined  and 
adjusted  lives  of  the  constituent  tissues. 
By  his  brilliant  exposition  of  this  fruitful 
idea,  he  had  opened  up  new  ways  for  an 
exact  experimental  analysis  of  physiological 
phenomena.  But  in  the  detailed  applica- 
tion of  this  idea,  which  in  the  flush  of  his 
youthful  enthusiasm  he  strove  to  make 
complete  and  symmetric,  undertaking  a 
task  the  doing  of  which  has  needed,  and 
still  needs,  the  continued  successive  labours 
of  many  inquirers,  he  often  went  astray. 
Moreover,  he  so  far  remained  under  the 

32 


PHYSIOLOGICAL   SCIENCE 

influence  of  that  vitalistic  teachino-  which 
in   spite    of  what   Haller    had    done,    was 
still    potent    in    the    latter     part     of    the 
eighteenth     century,    that    he     based    his 
whole    exposition  on    the    idea    that    vital 
manifestations  are  the  result  of  a  conflict 
between  vital  forces  on  the  one  hand  and 
physico-chemical  forces  on  the   other  :  he 
taught  that  these  were  essentially  antagonis- 
tic, and  that  the  latter  have  full  play  only 
when  the  former  vanish  in  death.     Had  he 
lived  longer  he  might  perhaps  have  freed 
himself  from  the  many  conceptions  which 
lessen  the  value  of  his  great  v/ork  ;   but  he 
was  taken  away  too  soon,  for  he  died  at 
the  early  age  of  31,  just  about  the  age  at 
which  Bernard  began  to  publish.      And,  as 
often  happens,  the  parts  of  his  labours  which 
were  specious  and  misleading  appeared  the 
most  tempting  to  many  vv^ho  followed  him. 
These     dwelt     more      on     his     view     of 

33  D 


CLAUDE   BERNARD 

organic  sensibility  and  contractility  to 
which  his  division  into  organic  and  animal 
life  had  led  him,  than  on  his  con- 
ception that  each  tissue  had  its  own  life, 
and  were  more  pleased  with  his  epigram- 
matic definition  of  life  as  the  sum  of 
forces  which  resist  death  than  with  his 
laborious  attempts  to  define  the  characters 
of  the  several  tissues. 

Bichat,  by  dividing  the  vital  principle 
and  distributing  it  over  the  several  tissues, 
attributing  to  it  different  functions  in 
different  parts,  in  reality  dealt  a  deathblow 
to  the  old  vitalistic  conceptions.  But  he 
did  not  live  long  enough  to  grasp  the 
conclusion  to  which  his  labours  were  lead- 
ing, and  his  successors  for  the  most  part 
stopped  also  where  he  himself  had  left  off. 

Vitalism  was  thus  dominant  in  France, 
especially  dominant  perhaps  in  medical 
doctrines.      Some  indeed  maintained   that 

34 


PHYSIOLOGICAL   SCIENCE 

the  phenomena  of  living  bodies  could  never 
be  the  subject  of  exact  experimental  inquiry. 
Bernard  himself  states  that  in  his  earlier 
days  he  heard  a  professor  of  surgery,  one 
Gerdy,  say,  "When  the  physiologist  asserts 
that  vital  phenomena  remain  identical 
under  identical  conditions,  he  proclaims 
an  error  ;  such  is  only  true  of  non-living 
bodies." 

Within  physiology  itself  a  way  was 
opened  for  the  encouragement  of  experi- 
mental inquiry  by  the  development  of  a 
modified  vitalism  which  taught  that  the 
phenomena  of  living  bodies  might  be 
divided  into  two  classes  :  those  which  are 
the  outcome  of  chemico-physical  causes, 
and  those  which  are  not,  and  which  can  be 
attributed  only  to  the  action  of  a  vital 
principle  or  force.  The  former  may  be 
studied  by  ordinary  experimental  methods ; 
the  latter  are  beyond  inquiry,  "  their  causes 

35 


CLAUDE    BERNARD 

mock    alike     our     conceptions    and     our 
curiosity."  ^ 

Such  was  the  scientific  attitude  of 
Magendie,  who,  when  Bernard  began  his 
medical  studies,  stood  far  above  all  others, 
as  the  physiologist  of  France.  Flourens, 
the  showy  Perpetual  Secretary  of  the  Aca- 
demy of  Sciences,  who  approached  physio- 
logy rather  from  the  side  of  natural  science 
than  from  that  of  medicine,  had,  it  is  true, 
achieved  a  great  reputation  ;  but,  even 
when  we  have  made  every  allowance  for 
his  work  on  the  semicircular  canals,  his 
influence  on  physiology,  when  carefully 
weighed,  falls  far  below  that  which  the 
fame  he  enjoyed  during  his  lifetime  indi- 
cated. Longet  and  others  were  doing 
praiseworthy  though  limited  work.  But 
Magendie  was  the  man  who,  during  the 

^   Magendie,  "  Phen.    phys.   de   la   Vie,"   vol.    ii. 
p.  47. 

36 


PHYSIOLOGICAL   SCIENCE 

first  half  of  the  century,  was  justly  acknow- 
ledged as  the  physiologist  of  France. 

And  that  scientific  attitude  of  his,  to 
which  we  have  just  referred,  was  indirectly 
the  cause  of  his  experimental  activity. 
Having  paid  his  tribute  to  vitalism  by 
admitting  that  some  of  the  phenomena  of 
living  beings  were  beyond  the  scope  of 
experimental  investigation,  he  felt  free  to 
throw  himself,  without  any  restraint  what- 
ever, into  the  research  of  those  phenomena 
which  he  deemed  open  to  experiment. 
He  became  in  this  way  the  apostle  of 
physiological  experiment.  While  in  Ger- 
many, as  we  have  just  said,  researches  of 
an  experimental  character  were  relatively 
rare,  and  rarer  still  in  England  and  else- 
where, Magendie  from  the  very  commence- 
ment of  his  career,  in  1807  or  thereabouts, 
was  unceasing  in  experimental  investiga- 
tions ;  he  did  alone  with  his  own  hand  in 

37 


CLAUDE   BERNARD 

France  as  much  as,  or  more  than,  was 
being  done  by  others  in  all  other  lands  ; 
and  though,  as  we  have  said,  the  spirit  of 
such  a  kind  of  inquiry  was  present  both 
in  Germany  and  elsewhere,  and  the  workers 
in  these  lands  had  no  need  to  go  abroad 
to  be  taught  the  true  method  of  inquiry, 
there  can  be  no  doubt  that  the  influence 
of  Magendie's  example,  as  one  who  sub- 
jected every  physiological  question  which 
he  touched  to  the  test  of  experiment,  was 
felt  far  and  wide,  and  passed  to  countries 
other  than  his  own. 

Magendie's  contributions  to  physiolo- 
gical science  were  many  and  great  ;  the 
exact  and  full  proof  v/hich  he  brought 
forward  of  the  truth  which  Charles  Bell 
had  divined  rather  than  demonstrated,  that 
the  anterior  and  posterior  roots  of  spinal 
nerves  have  essentially  different  functions, 
a    truth    which    is    the    very    foundation 

38 


PHYSIOLOGICAL   SCIENCE 

of  the  physiology  of  the  nervous  system, 
Is  enough  by  itself  to  mark  him  as  a 
great  physiologist ;  and  he  did  much 
else  besides.  But  all  his  lasting  results, 
even  when  their  fullest  value  is  allotted  to 
them,  are  incommensurate  with  his  activity. 
If  he  did  many  experiments  which  bore 
adequate  fruit,  he  did  also  many  which 
were  misleading  and  many  which  were 
useless.  For  his  worship  of  the  experi- 
mental method  came  very  near  to  being 
idolatry.  Repelled  by  the  sterile  dis- 
cussions in  which  the  vitalists  and  other 
doctrinaires  of  the  day  spent  their  intel- 
lectual activity,  he  was  driven  towards  the 
other  extreme,  and  arrived  almost  at  the 
position  of  substituting  experiment  for 
thinking.  So  far  from  regarding  an  expe- 
riment as  a  thing  to  be  had  recourse  to  as 
a  test,  by  v/hich  to  determine  whether  a 
view  derived  from  observation  and  medi- 

39 


CLAUDE   BERNARD 

tation  were  true  or  no,  he  rather  thought, 
or  seemed  by  his  practice  and  indeed  his 
teaching  to  think,  that  an  experiment  was 
the  first  step  towards  getting  light.  He 
so  to  speak  thrust  his  knife  here  and 
there,  to  see  what  would  come  of  it.  He 
indeed  confessed,  in  a  way,  that  this  was 
the  nature  of  his  method.  Speaking  of 
himself  he  says,  '^  Every  one  is  fond  of 
comparing  himself  to  something  great 
and  grandiose,  as  Louis  XIV.  likened 
himself  to  the  sun,  and  others  have  had 
like  similes.  I  am  more  humble.  I  am 
a  mere  street  scavenger  (^chiffonnier)  of 
science.  With  my  hook  in  my  hand  and 
my  basket  on  my  back,  I  go  about  the 
streets  of  science,  collecting  what  I  find." 
Hence,  when  Bernard  entered  upon  his 
post  as  assistant  to  Magendie,  he  found 
himself  subject  to  two  influences  antago- 
nistic the  one  to  the  other.     On  the  one 

40 


PHYSIOLOGICAL   SCIENCE 

hand,  he  had  to  listen,  especially  in  medical 
circles,  to  expositions  of  vitalistic  views, 
to  the  depreciation  of  the  experimental 
method  as  a  false  guide  in  inquiries  con- 
cerning the  phenomena  of  living  beings. 
On  the  other  hand,  he  was  brought  into 
daily  touch  with  a  man  who  scoffed  at  all 
theory  and  ridiculed  reasoned  discussions, 
and  who,  while  he  refused  to  apply  the 
test  of  experiment  to  certain  questions  of 
physiology,  exalted  experiment  in  the 
regions  in  which  he  did  apply  it,  to  the 
almost  complete  exclusion  of  other  means 
of  inquiry. 

In  spite  of  the  personal  influences  which 
Magendie  must  have  exerted  on  him,  the 
young  assistant  had  the  genius  to  strike 
out  a  path  for  himself.  While  recognising, 
as  clearly  as  did  his  master,  the  value  of 
experiment  as  the  final  test  of  all  phy- 
siological   views,    he,    on    the    one  hand, 

41 


CLAUDE   BERNARD 

deposed  experiment  from  its  false  throne, 
making  it  the  servant  and  not  the  master 
of  reasoned  speculations  ;  and,  on  the  other 
hand,  as  we  shall  see,  extended  its  domains, 
showing  how,  under  proper  use,  it  could 
be  applied  without  distinction  to  all  the 
phenomena  of  life.  In  doing  so  the  pupil 
went  far  beyond  the  master  ;  that  which 
the  multitude  of  blind  experiments  made 
by  the  latter  have  left  behind  as  a  lasting 
contribution  to  physiological  science  is  but 
little  compared  to  that  which  has  come 
from  the  much  fewer  experiments  of  the 
former,  guided  as  they  were  in  every  case 
by  previous  meditation  and  thought. 


42 


Ill 

Early    Labours 

BY  his  appointment  as  p'eparateur  to 
Magendie  Bernard  was  fairly  started 
on  the  career  of  an  experimental  physio- 
logist. Outside  his  duties  at  the  College 
de  France,  he  had  to  devote  some  time  to 
the  delivery  of  private  courses  of  lectures 
in  order  to  eke  out  his  slender  income  ; 
the  rest  he  gave  up  to  research,  his  investi- 
gations being  carried  on  chiefly  if  not  ex- 
clusively in  some  place  or  other  which  he 
had  temporarily  fitted  up  as  a  private 
laboratory,  or  in  the  chemical  laboratory 
of  one  or  other  of  his  friends.     There  was 

43 


CLAUDE   BERNARD 

not  room  for  him,  it  would  appear,  to  con- 
duct his  own  private  work  in  the  labora- 
tory of  the  College  de  France. 

In  May,  1843,  ^^  published  his  first 
communication,  "Recherches  anatomiques 
et  physiologiques  sur  la  corde  du  tympan, 
pour  servir  a  Thistoire  de  I'hemiplegie 
faciale,"  ^  followed,  in  December  of  the 
same  year  by  his  *' These  pour  le  Doctorat 
en  medecine "  having  for  title  "  Du  sue 
gastrique  et  de  son  role  dans  la  nutri- 
tion." 

The  work  on  the  chorda  tympani,  in 
which  we  may  recognise  the  influence  of 
Magendie's  long  continued  labours  on  the 
functions  of  nerves,  is  in  part  anatomical 
and  in  part  physiological.  The  former  part 
is  one  of  the  many  illustrations  of  Bernard's 
exact  and  extensive  anatomical  knowledge, 
in  acquiring  which  he  was  greatly  aided  by 
^"Annales  medico-psychologiques,"  I.,  1843,  p.  408. 

44 


EARLY   LABOURS 

his  remarkable  manual  dexterity  in  dissec- 
tion, a  knowledge  and  dexterity  which  some 
years  later  was  displayed  in  his  contri- 
butions to  Huette's  popular  work  on  sur- 
gical anatomy.  Li  the  physiological  part 
he  deals  chiefly  with  the  relations  of  the 
nerve  to  taste  and  hearing  ;  and  it  is 
interesting  to  note  that  though  he  was 
destined  hereafter  to  carry  out  many  im- 
portant researches,  of  which  the  action  of 
the  chorda  tympani  on  the  submaxillary 
gland  was  the  pivot,  so  that  this  first 
memoir  serves  in  a  certain  sense  as  the 
beginning  of  long  series  of  investigations 
on  the  relations  of  nerves  to  secretion, 
he  began  by  a  false  step.  He  contended 
that  the  chorda  had  no  influence  on  the 
secretory  activity  of  the  submaxillary  gland 
or  on  the  contractile  efforts  of  its  duct. 

The  thesis  on  the  gastric  juice  was  still 
more  emphatically  the  first  of  a  long  series 

45 


CLAUDE   BERNARD 

of  investigations  ;  as  we  shall  see  it  was  the 
first  step  in  an  inquiry  which  before  long 
led  him  to  the  discovery  of  the  glycogenic 
function  of  the  Jiver.  The  main  result 
made  known  in  the  thesis  was  that  while 
cane  sugar  injected  directly  into  the  veins 
readily  appeared  in  the  urine,  this  did  not 
occur  when  the  cane  sugar,  previous  to  the 
injection,  had  been  subjected  to  the  in- 
fluence of  the  gastric  juice.  He  inferred 
that  cane  sugar  as  such  in  the  blood  was 
unsuitable  for  the  nutrition  of  the  tissues, 
and  was  consequently  cast  out,  but  tkat  by  the 
influence  of  gastric  juice  it  was  so  modified 
as  to  become  suitable,  and  in  that  condition 
was  retained  and  utilised.  In  this  simple 
result  lay  the  germ  of  much  that  was  to  come 
afterwards.  The  paper  is  also  interesting 
as  containing  the  record  of  the  experiment 
which  has  since  become  classical,  of  the 
simultaneous  injection  of  potassium  ferro- 

46 


EARLY   LABOURS 

cyanide,  and  ferrous  sulphate,  by  which  he 
showed  that  the  acid  of  gastric  juice  makes 
its  appearance  on  the  surface  and  not  in 
the  depths  of  the  gastric  glands. 

These  two  researches  in  a  way  illustrate, 
when  put  together,  the  main  idea  which 
governed  almost  the  entire  course  of 
Bernard's  labours.  The  action  of  the 
nervous  system  on  the  chemical  changes 
which  constitute  the  basis  of  nutrition,  was 
a  problem  always  present  to  his  mind,  and 
one  which  he  attempted  to  solve  on  the 
one  hand  by  experimental  investigations  on 
nerves,  and  on  the  other  by  direct  chemical 
researches ;  he  was  almost  always  busy 
with  the  one  or  with  the  other,  and  happy 
when  he  was  employing  the  two  methods 
at   the  same   time  and   in  concert. 

The  reference  to  facial  paralysis  in  his 
paper  on  the  chorda,  indicates  also  that  from 
the  outset  of  his  career  he  had  grasped  the 

47 


CLAUDE    BERNARD 

view  that  physiology  may  fitly  be  called 
experimental  medicine,  the  results  of  the 
laboratory  being,  with  due  precautions, 
available  for  use  at  the  bedside. 

His  succeeding  researches  were  carried 
out  much  on  the  same  line  as  the  first  two. 
He  investigated  the  spinal  accessory  nerve, 
and  he  continued  his  studies  in  digestion, 
and  other  problems  of  chemical  physiology, 
sending  in  for  his  thesis  at  the  "  Concours 
pour  I'agregation"  a  memoir  on  the  colour- 
ing matters  present  in  the  human  body. 

No  very  remarkable  result  was  obtained 
in  any  of  the  above  researches,  but  in  the 
year  1846,  in  the  course  of  an  investigation 
on  the  differences  in  digestion  and  nutrition 
between  herbivora  and  carnivora,  an  in- 
vestigation which  he  carried  on,  as  he  did 
many  of  his  earlier  chemical  researches,  in 
company  with  his  friend  Barreswil,  he  made 
an    observation    which    proved    to   be   the 

48 


EARLY   LABOURS 

starting-point  of  his  first  really  important 
discovery. 

"We  had  observed,"  says  he,^  "that 
when  we  introduced  fat  into  the  stomach 
of  a  rabbit,  the  fat  passing  on  from  the 
stomach  was  not  modified  until  it  had 
reached  a  certain  distance  from  the 
stomach  at  a  point  much  lower  than 
that  at  which  a  like  change  takes  place  in 
the  case  of  dogs.  The  same  difference 
manifested  itself  in  the  absorption  of  the 
fat  by  the  lacteals.  We  sav/  that  these  in 
the  rabbit  first  became  white  and  opaque 
through  the  presence  of  fat  at  a  consider- 
able distance  from  the  pylorus,  whereas 
in  dogs  the  change  was  visible  at  the  very 
commencement  of  the  duodenum.  This 
difference  between  dogs  and  rabbits  as  to 
the  place   at  which  the  modification  and 

^  Le9ons   de  Physfologie  Experimentale.     Cours. 
1855,  11.,  p.  178. 

49  E 


CLAUDE   BERNARD 

absorption  of  fat  begins  to  take  place 
having  been  confirmed  by  repeated  obser- 
vation, it  was  natural  to  look  for  the 
cause  in  some  special  disposition  of  the 
intestines ;  and  now  we  noted  that  the 
difference  coincided  with  a  difference  in 
the  entrance  of  the  pancreatic  duct  into  the 
intestine.  In  the  dog  the  pancreatic  juice 
is  discharged  into  the  intestine  quite  close 
to  the  pylorus,  whereas  in  the  rabbit  the 
principal  pancreatic  duct  opens  into  the 
intestine  at  a  point  thirty  or  thirty-five 
centimetres  below  the  opening  of  the  biliary 
duct.  It  was  precisely  at  this  point  that 
the  change  in  the  fat  began  to  take  place, 
and  that  the  lacteals  were  able  to  absorb 
it." 

This  observation  was  the  starting-point 
of  Bernard's  remarkable  researches  on  the 
properties  and  uses  of  the  pancreas.  And 
it   may  be  noted  that   in  this,   as  indeed 

50 


EARLY    LABOURS 

in  some  other  Instances,  Bernard  was  led 
to  an  important  truth  by  an  observation 
not  wholly  accurate.  It  was  pointed  out 
afterwards,  and  has  become  generally 
accepted,  that  this  disposition  of  the  fat 
and  the  lacteal  contents  in  the  rabbit  is 
not  invariable,  indeed,  that  the  appear- 
ances described  by  Bernard  are  seen  not 
always,  but  only  when  the  abdomen  is 
opened  at  a  particular  time  after  the 
taking  of  the  fat.  Nevertheless,  the 
observation  did  start  Bernard  on  a  fruitful 
inquiry  into  the  action  of  the  pancreatic 
juice,  and  with  that  instinct  of  genius  which 
was  one  of  his  marked  characteristics,  he 
deserted  the  search  into  the  differences 
between  herbivora  and  carnivora  for  the 
new  line  of  investigation  which  the  obser- 
vation in  question  suggested. 

The    new   research   was    not,    however, 
completed  for  some  little  time.     The  first 

51 


CLAUDE   BERNARD 

notice  of  the  results  obtained  were  made 
known  to  the  Societe  Philomathique  in 
April,  1848,  and  a  somewhat  fuller  account 
was  presented  to  the  Societe  de  Biologie 
in  February,  1849.  ^^^  ^^  ^^^  ^^^ 
until  1856  that  he  published  the  complete 
"  Memoire  sur  le  pancreas  et  sur  le  role 
du  sue  pancreatique,"  which  appeared  as 
a  supplement  to  the  "  Comptes  Rendus  " 
of  the  Academie  des  Sciences  for  that  year. 
At  the  time  when  Bernard  took  the 
matter  in  hand  our  knowledge  of  the 
action  of  the  pancreatic  juice,  and  indeed 
of  intestinal  digestion  was  of  the  scantiest. 
In  Johannes  Miiller's  great  work,  pages  are 
devoted  to  gastric  digestion,  Beaumont's 
observations  on  Alexis  St.  Martin,  the 
Canadian  with  the  accidental  gastric  fistula, 
being  dwelt  upon  at  length  ;  indeed,  the 
changes  undergone  by  the  food  in  the 
stomach  are  treated  as  if  they  were  almost 

52 


EARLY   LABOURS 

identical  with  digestion  as  a  whole.  A  good 
deal  is  said  it  is  true  about  the  bile  ;  but  the 
pancreas  is  passed  over  almost  in  silence. 
"  The  excellent  researches  of  Tiedemann 
and  Gmelin "  are  quoted  as  containing 
''  all  that  we  know  with  certainty  relative 
to  the  changes  which  the  chyme  under- 
goes in  the  intestine  ;  "  and  all  that  these 
authors  have  to  suggest  is  the  possibility 
"that  the  casein  of  the  pancreatic  secretion 
containing  a  large  proportion  of  nitrogen 
yields  a  portion  of  this  element  to 
different  ingredients  of  the  alimentary 
substances  which  contain  less  nitrogen,  so 
as  to  reduce  itself  to  their  standard  in  this 
respect,  and  to  convert  them  into  albu- 
men." 

Let  this  vague  conception  be  compared 
with  the  knowledge  which  we  at  present 
have  of  the  several  distinct  actions  of  the 
pancreatic  juice,  and  of  the  predominant 

53 


CLAUDE   BERNARD 

importance  of  this  fluid  not  only  in  intes- 
tinal digestion,  but  in  digestion  as  a  whole, 
and  it  will  be  at  once  seen  what  a  great 
advance  has  taken  place  in  this  matter 
since  the  early  forties.  That  advance  we 
owe  in  the  main  to  Bernard.  Valentin,  it 
is  true,  had  in  1844  not  only  inferred  that 
the  pancreatic  j  uice  had  an  action  on  starch, 
but  confirmed  his  view  by  actual  experiment 
with  the  juice  expressed  from  the  gland  ; 
and  Eberle  had  suggested  that  the  juice  had 
some  action  on  fat  ;  but  Bernard  at  one 
stroke  made  clear  its  threefold  action.  He 
showed  that  it,  on  the  one  hand,  emulsi- 
fied, and,  on  the  other  hand,  split  up  into 
fatty  acids  and  glycerine,  the  neutral  fats 
discharged  from  the  stomach  into  the 
duodenum  ;  he  clearly  proved  that  it  had 
a  powerful  action  on  starch,  converting  it 
into  sugar  ;  and,  lastly,  he  laid  bare  its 
remarkable    action    on    proteid    matters. 

54 


EARLY   LABOURS 

Pointing  out  that  the  bile  precipitates  the 
products  of  the  gastric  digestion  of  proteid 
matters,  and  puts  an  end  to  peptic  changes, 
he  went  on  to  show  that  the  pancreatic 
juice  acted  subsequently  as  well  on  these 
precipitated  matters  as  on  those  proteid 
constituents  of  a  meal  which  had  escaped 
solution  in  the  stomach.  *'  It  is,  in  fact, 
the  pancreatic  juice  which  has  the  special 
property  of  completely  dissolving  these 
two  kinds  of  material,  for  the  digestion  of 
nitrogenous  substances  is  far  from  being 
completed  in  the  stomach,  though  this  is 
the  accepted  view.  Two  acts,  perfectly  dis- 
tinct, take  place  in  the  stomach,  and  in  the 
intestine,  the  one  duly  following  the  other. 
Gastric  digestion  is  only  a  preparatory  act." 
In  carrying  out  the  observations  which 
supply  the  proof  of  this  energetic  and  mul- 
tiple action  of  the  pancreatic  juice,  Ber- 
nard took  a  hint  from  Blondlot,  who  in 

55 


CLAUDE   BERNARD 

1843  ^^d  introduced  the  method  of  the 
artificial  gastric  fistula.  He  not  only  him- 
self early  and  repeatedly  used  the  gastric 
fistula,  but,  extending  the  method,  brought 
into  use  the  pancreatic  fistula.  Regnier  de 
Graaf  had,  it  is  true,  so  early  as  1662, 
succeeded  in  making  some  sort  of  pan- 
creatic fistula,  but  in  a  very  imperfect  and 
fruitless  manner.  It  was  Bernard  who 
made  the  operation  really  practicable  and 
useful. 

When  we  realise  how  deeply  our  pre- 
sent knowledge  of  the  varied  and  powerful 
action  of  pancreatic  juice  has  affected  our 
present  conceptions,  not  only  of  the  diges- 
tive act,  but  also  of  the  processes  of 
nutrition,  and  when  we  remember  that, 
making  all  allowance  for  the  researches, 
subsequent  to  those  of  Bernard,  of  Corvi- 
sait,  and  especially  of  Kiihne,  on  the 
proteolytic  action  of  the  juice,  not  only  the 

56 


EARLY   LABOURS 

foundation,  but  even  the  larger  part  of  the 
whole  edifice  of  that  knowledge,  is  to 
be  found  in  Bernard's  memoir,  we  may  be 
well  prepared  to  commend  the  action  of 
the  Academie  des  Sciences,  when  in  1850 
it  awarded  to  the  researches  embodied  in 
that  memoir  the  prize  of  Experimental 
Physiology. 

By  the  publication  of  that  memoir, 
moreover,  not  only  France,  but  men  of 
science  in  all  lands,  were  made  aware  that 
a  young  physiological  inquirer  of  striking 
powers  had  arisen  in  Paris.  Yet  the 
merits  of  the  research  on  the  pancreas 
were  soon  to  be  eclipsed  by  results  of 
a  still  higher  order,  and  of  far  more  com- 
manding influence,  reached  by  the  efforts 
of  the  same  brilliant  investigator. 

Before  we  leave  these  earlier  labours, 
however,  one  more  research  must  be 
mentioned,  a  research    in    which   Bernard 

57 


CLAUDE   BERNARD 

came  to  the  aid  of  his  master,  Magendie. 
In  supplying  in  1822  the  direct  and 
complete  proof  of  C.  Bell's  views  as  to 
the  separate  functions  of  the  anterior  and 
posterior  roots  of  spinal  nerves,  and  in 
later  experiments  of  the  same  kind  in 
1829  and  1839,  Magendie  had  sometimes 
found  the  anterior  roots  sensitive.  He, 
however  (or  Longet,  for  this  observer 
claimed  the  merit  of  the  observation), 
also  observed  that  this  sensibility  of  the 
anterior  root  was  in  some  way  dependent 
on  the  posterior  root,  was  a  sensibility 
imparted  to  the  anterior  root  and  not 
inherent,  like  the  sensibility  of  the  pos- 
terior root  in  the  root  itself;  and  the 
sensibility  in  question  accordingly  received 
the  name  of  "  recurrent  sensibility.'*  The 
phenomena,  however,  were  exceedingly  in- 
constant ;  sometimes  the  anterior  root  was 
found  to  be  sensitive,  but  more  often  the 

58 


EARLY    LABOURS 

results  of  a  search  for  sensibility  were 
negative.  So  uncertain  was  the  matter 
that  Longet  was  ultimately  led  to  deny 
altogether  the  existence  of  any  such  thing 
as  recurrent  sensibility. 

Bernard,  attending  Magendie's  course 
in  1839,  and  witnessing  the  inconstant 
results  of  the  experiments  on  this  recurrent 
sensibility,  concluded,  with  the  quick  in- 
sight of  a  true  inquirer,  that  the  incon- 
stancy must  be  due  to  a  want  of  knowledge 
of  the  conditions  under  which  the  ex- 
periment ought  to  be  conducted.  And 
he  set  about  to  determine  what  those 
conditions  were.  A  few  years  later  he 
had  laid  hold  of  the  conditions,  and  in 
1 847  he  published  two  papers  i  in  which, 
by  showing  what  circumstances  favoured 
and   what   hindered   the   development    of 

^  "  Soc.  Philom.,"   1847,  p.  79,  and  "  Comptes 
Rendus,"  xxv.  pp.  104,  106,  1847. 

59 


CLAUDE    BERNARD 

recurrent  sensibility,  he  rescued  his  master's 
discovery  from  the  disrepute  into  which  it 
had  fallen.  The  experiments  and  argu- 
ments briefly  summarised  in  the  two 
papers  just  spoken  of  are  more  fully  set 
forth  in  the  lectures  on  the  nervous  system 
which  Bernard  published  many  years  later. 
The  question  of  recurrent  sensibility  does 
not  possess  to-day  the  importance  which 
it  seemed  to  have  then  ;  the  researches  of 
Bernard  in  relation  to  it  are  worthy 
however  of  special  note,  since  they  bear 
the  marks  of  the  same  power  to  solve 
an  experimental  problem,  which  later  on 
brought  in  such  rich  results. 


60 


IV 

Glycogen 

T  IMPORTANT  as  was  Bernard's  dis- 
■A  covery  of  the  action  of  the  pancreatic 
juice,  he  soon  came  upon  a  far  greater  one. 
And  the  story  of  how  he  came  upon  it  is 
worth  telling  in  detail,  since  it  illustrates 
in  a  striking  manner  how  an  alert,  in- 
quiring mind,  seizing  at  once  upon  the 
hints  which  Nature  gave,  was  led  into 
a  wholly  new  path,  and,  cautiously  advan- 
cing step  by  step,  as  the  way  opened  up, 
was  enabled,  by  almost  its  own  unassisted 
labours,  to  give  to  the  world  a  new  truth, 

6i 


CLAUDE   BERNARD 

not  as  a  mere  rough   conception,  but  as 
a  highly  finished  work. 

At  the  time  when  Bernard  began  his 
physiological  studies,  the  views  which  the 
great  Dumas  had  brilliantly  expounded 
in  the  "  Essai  sur  la  Statique  Chimique 
des  Etres  Organises,"  written  by  himself 
and  the  agronomic  chemist  Boussingault, 
may  be  said  to  have  been  dominant  among 
biologists.  According  to  those  views, 
animals  and  plants  presented  a  complete 
chemical  contrast,  the  one  to  the  other. 
The  chemical  token  of  the  plant  was  that 
out  of  the  elements  existing  in  the  in- 
organic world  it  built  up  the  complex 
organic  compounds,  the  carbohydrates,  the 
fats,  the  proteids,  and  the  like,  which 
formed  the  chemical  basis  of  its  body. 
The  chemical  token  of  the  animal  was 
that,  by  feeding,  it  received  these  ready- 
made  organic  compounds    into    its  body, 

62 


\ 


GLYCOGEN 

and  destroyed  them,  resolving  them  again 
Into  inorganic  constituents,  and  utilising 
that  resolution  for  the  needs  of  its  life. 
The  animal  might  modify  the  vegetable 
compounds  and  give  them  an  animal 
character ;  but  it  never  made  anything 
anew.  Matter  passed  through  a  cycle 
rising  up  through  the  constructive  labours 
of  the  plant  Into  the  organic  compounds 
of  the  living  body,  and  falling  back 
again  by  the  destructive  labours  of  the 
animal  into  the  inorganic  compounds  of 
the  world  which  was  not  alive.  The 
contrast  was  held  to  be  complete;  it  was 
asserted  that  the  animal  body  never  built 
up,  never  manufactured,  either  fat,  or 
carbohydrate,  or  proteid ;  all  of  any  of 
these  present  in  the  animal  body  had  been 
brought  to  it  in  its  food. 

These  were  the  dominant  views,  though 
the  voice  of  heresy  had  already  made  itself 

63 


CLAUDE    BERNARD 

heard.  In  the  spring  of  1843,  ^^^  Y^^^ 
m  which  Bernard  published  his  first  papers, 
the  calm  of  the  Academic  des  Sciences  was 
broken  by  a  lively  discussion.  Payen, 
a  chemist  who  was  an  authority  on  the 
chemistry  of  food,  communicated  a  paper 
by  Dumas,  Boussingault,  and  himself, ^ 
in  which  it  was  insisted  that  the  fat  already 
present  in  the  fodder  was,  as  shown  by 
careful  analysis,  sufficient  to  supply  the  fat 
found  in  the  body  of  the  fattened  beast. 
Liebig  intervened  in  the  discussion  by  a 
letter  in  which  he  quoted  new  experiments 
by  Gundlach  at  Giessen,  confirming  Huberts 
old  observations  of  1780,  that  bees  fed  on 
sugar  alone  formed  v/ax,  and  disproving 
the  criticism  that  the  bees  had  furnished 
the  wax  out  of  the  previous  store  of  fat  in 
their  own  bodies.     He  further  showed  that 

I  "Recherches  sur  rengraissement  des  bestiaux  et 
la  formation  du  lait." 

64 


GLYCOGEN 

the  fat  accumulated  in  the  bodies  of  fattened 
geese  far  exceeded  the  supply  furnished  by 
the  fat  of  their  food,  and  while  twitting 
Dumas  for  refusing  to  believe   that  starch 
or  sugar  could  be  changed  into  fat,  while 
he  assumed  that  mere  waxy  material  could 
be  so  changed,   though    the   change    was, 
from  a  chemical  laboratory  point  of  view, 
almost  as  difficult,  clenched  his  argument 
by  showing  that  when  a  cow  was  fattened, 
the    excreta  during    the    fattening    period 
contained  as  much  fat  as  the  food  taken. 
Dumas  and  his  friends  remained  apparently 
unconvinced,  though,  by  an  irony  of  fate, 
in   the  very  next  year  Dumas  announced 
to    the    Academy    that    observations    con- 
ducted  by    Milne -Edwards   and    himself 
on    bees   fully   confirmed    the    validity  of 
Ruber's  old  argument. 

It   was    while   men's   opinions   on    the 
chemistry  of  nutrition  were  in  this  con- 

65  F 


CLAUDE    BERNARD 

dition  that  Bernard  took  up  a  research 
on  the  physiology  of  sugar.  His  second 
published  paper,  his  thesis  for  the  doc- 
torate, on  the  action  of  the  gastric  juice, 
was  the  initial  step  in  this  research.  His 
active  mind,  in  turning  from  poetry  to 
science,  had  lost  nothing  of  its  early 
ambition.  The  task  which  he  had  proposed 
to  himself  was  no  less  a  one  than  to  trace 
out  the  successive  transformations  which 
the  food  stuffs,  the  dominant  substances 
of  food,  underwent  within  the  animal  body. 
His  first  result,  embodied  in  his  thesis, 
was  that  cane  sugar  was  acted  upon  by 
gastric  juice,  and  underwent  through  the  in- 
fluence of  that  fluid  its  first  transformation, 
namely,  a  change  into  dextrose  (glucose) 
as  a  necessary  preparation  for  its  being 
utilised  by  the  tissues. 

He  had  intended  to  study  all  the  three 
great  classes  of  food  stuffs,  carbohydrates, 

66 


GLYCOGEN 

fats  and  proteids  ;  but  he  began  with  the 
first,  and  found  the  study  of  these  so  expan- 
sive that  he  never  got  beyond  them.  He 
began  with  sugars,  partly  because  they 
were  the  more  simple,  and  partly  because 
he  had  become  early  fascinated  with  the 
problems  suggested  by  the  disease  diabetes; 
he  was  anxious  to  explain  the  cause  of  this 
excess  of  sugar  in  diabetes,  and  so  by  good 
fortune  to  find  a  remedy  for  it. 

The  plan  of  research  which  he  marked 
out  for  himself  was  somewhat  as  follows. 
Tiedemann  and  Gmelin  had  shown  that 
in  the  alimentary  canal  starch  is  converted 
into  dextrose  before  being  absorbed ;  he 
had  himself  shown,  as  we  have  just  said, 
that  cane-sugar — sugar  of  the  first  species, 
as  he  called  it — is  also  converted  into 
dextrose,  into  sugar  of  the  second  species. 
All  carbohydrates,  then,  may  be  considered 
as    passing    into   the    blood   as   dextrose. 

67 


CLAUDE    BERNARD 

What  becomes  of  this  dextrose  ?  What 
fate,  what  transformation,  aAvaits  it? 
Bernard  proposed  to  himself  to  track  out 
dihgently  the  dextrose,  introduced  into 
the  body  from  the  alimentary  canal,  along 
the  portal  vein  to  the  liver,  from  the  liver 
through  the  right  heart  to  the  lungs,  and 
then  from  the  lungs  through  the  left  heart 
to  the  several  tissues  of  the  body.  "  At 
one  or  other  of  these  stations  I  shall  find," 
he  said  to  himself,  "  that  the  dextrose  dis- 
appears, is  destroyed,  or  is  in  some  way  or 
other  changed.  If,  having  found  the  station 
of  destruction,  I  am  able  to  suppress  the 
activity  of  this  station,  sugar  will  accumu- 
late in  the  blood,  and  a  condition  of 
diabetes  will  be  brought  about.  (He  had 
already  satisfied  himself  that  the  essence 
of  diabetes  was  an  excess  of  sugar  in  the 
blood.)  If  I  can  thus  artificially  produce 
diabetes,  the  way  will  be  opened  for  the 

68 


GLYCOGEN 

discovery  of  curative  means."  All  this 
he  tells  us  himself  i;  the  great  discovery 
he  was  about  to  make  was  no  haphazard 
dive  in  Nature's  full  pocket ;  it  was  the 
reward  of  a  carefully  planned  enterprise. 
And  the  crown  fell  into  his  hands  in 
this  wise. 

He  fed  a  dog  on  a  diet  rich  in  sugar  and 
sugar-furnishing  material,  and,  killing  it  at 
the  height  of  digestion,  examined  the  blood 
leaving  the  liver  by  the  hepatic  veins,  to 
to  see  if  there  were  any  destruction  of 
sugar  in  the  liver.  It  is  perhaps  worthy 
of  notice  as  illustrating  how  "  there  is  a 
time  for  everything,"  how  many  things, 
some  of  them  little,  contribute  to  a  result, 
that  the  search  for  sugar  in  the  tissues  and 
fluids  of  the  animal  body,  to  which  Bernard 
had  set  himself,  was  just  at  that  time 
rendered  much  easier  by  Bernard's  friend 

^  "  Nouvelle  fonction  du  foie." 

69 


CLAUDE    BERNARD 

and  fellow  worker,  the  chemist  Barreswil, 
having  introduced  the  cupric  sulphate  test 
for  dextrose,  the  test  which  in  a  slightly 
modified  form  we  now  use  a  Fehling's 
test.  Bernard  found  abundant  sugar  in 
the  blood  of  the  hepatic  veins.  The 
liver,  therefore,  was  not  the  sought  for 
seat  of  the  disappearance  of  dextrose. 
"But,"  said  Bernard  to  himself,  ''how 
do  I  know  that  the  sugar  which  I  thus 
find  in  the  hepatic  vein,  is  the  same 
sugar  as  that  which  I  introduced  into  the 
portal  blood  through  the  food  ?  "  He 
accordingly  fed  another  dog  on  meat  only, 
on  sheep's  head,  having  previously  satisfied 
himself  that,  under  these  circumstances 
no  dextrose  was  present  either  in  the 
alimentary  canal  or  the  portal  blood, 
and  again  examined  the  blood  of  the 
hepatic  vein. 

To  his  great  astonishment  he  found  that 
70 


GLYCOGEN 

in  this  case  also  the  blood  of  the  hepatic 
vein  was  loaded  with  dextrose. 

Here  came  in  the  genius  of  the  true 
inquirer.  "  Why  !  "  said  he,  "  if  I  have 
made  no  mistakes,  I  have  in  this  experi- 
ment come  upon  the  production  of  sugar : 
the  liver  produces  sugar.  I  need  not 
labour  at  the  long  task  which  I  had 
marked  out  for  myself,  of  searching  for 
the  seat  of  the  destruction,  the  dis- 
appearance of  sugar,  so  that  by  suppressing 
that  I  might  indirectly  bring  about  the 
accumulation  of  sugar.  If  the  result 
which  I  have  just  got  is  confirmed  on 
repetition  of  the  experiment,  the  liver  is 
a  sugar-producing  tissue,  it  manufactures 
sugar  out  of  something  which  is  not  sugar, 
and  within  it  lies  the  secret  of  diabetes. 
Further,  Dumas  is  wrong  in  saying  that 
animals  do  not  construct,  that  the  liver  does 
not  construct  ;    the  liver   does    construct, 

71 


CLAUDE   BERNARD 

it  constructs  dextrose.  This  is  a  big  thing 
of  which  I  have  got  hold.  I  must  make 
sure  that  there  is  no  mistake  in  the  experi- 
ment, and  then  push  forward  as  far  as 
possible  the  lead  thus  given  me." 

He  set  about  to  test  his  result  in  every 
possible  way.  He  took  dogs  which  had 
*  been  starved,  and  dogs  which  had  been  fed 
for  some  time  on  meat  alone,  and  found 
in  both  cases  that  sugar,  while  absent  from 
the  alimentary  canal  and  from  the  chyle, 
was  present  in  the  blood  of  the  right  heart 
and  in  the  blood  of  the  portal  vein  close 
to  the  liver.  He  starved  a  dog  for  several 
days  in  order  to  get  rid  of  the  effects  of  a 
previous  mixed  diet,  then  fed  it  on  meat, 
and  found  sugar  as  before  in  the  hepatic 
vein  and  right  heart.  Opening  the  body 
of  a  dog  killed  in  full  digestion  he  placed 
ligatures  on  the  mesenteric  veins  at  some 
little  distance    from   the  intestine,  on  the 

72 


GLYCOGEN 

veins  from    the    pancreas,   on    the  splenic 
vein,  and  on  the  vena  portse  near  the  liver  ; 
he   found   no   sugar   in   the   blood   of  the 
mesenteric  veins  between  the  intestine  and 
the    ligature,   none    in    the    blood    of  the 
pancreatic  or  splenic  veins,  but  there  was 
sugar    in    the    portal     blood    between    the 
ligature    and    the    liver.      Obviously,    the 
sugar  in  the  latter   case  had  regurgitated 
from  the  liver  ;  it  was  clear  that  the  liver, 
and    not    the     spleen    or    the    pancreas, 
any  more  than  the  food  in  the  intestine, 
was    the    source    of    the    sugar.     And    he 
tound  that  a  simple  decoction  of  the  liver 
substance      invariably      contained      sugar. 
Lastly,  he  determined    that   the  sugar  in 
question  was  dextrose,  was  a  sugar  capable 
of     fermentation,    and     giving     all     the 
ordinary  tests  for  dextrose. 

He  now  felt  justified  in  making  known 
to  the  world  that  the  liver  was  capable  of 

n 


CLAUDE   BERNARD 

producing  sugar  not  brought  to  it  as  sugar 
in  the  food,  that  sugar  made  its  appearance 
in  the  liver  itself  by  an  act  which  seemed 
very  analogous  to  the  act  of  secretion  by  a 
secreting  gland,  and  which  therefore  might 
be  spoken  of  as  an  internal  secretion.  On 
the  28  th  of  August,  he  deposited  a  sealed 
packet  with  the  Academic  des  Sciences, 
and  on  the  15th  of  November  following, 
he  and  Earreswil  exhibited  at  the  Academic 
a  specimen  of  alcohol  obtained  by  fermen- 
tation from  sugar  of  the  liver,  their  efforts 
to  crystallise  the  sugar  having  so  far  been 
unsuccessful.  In  1 849  he  laid  before  the 
Societe  de  Biologic  a  fuller  account  of  his 
researches,!  and  again  in  1850  before  the 
Academic  des  Sciences.^ 

Continuing  his  researches,  examining  the 

^   "Mem.  Soc.  Biol.,"  1849,  PP-  ^21-133. 

-  "  Compt.   Rend.,"    xxi.     p.     571  ;    1850,    pp. 

571-574- 

74 


GLYCOGEN 

livers  of  many  different  kinds  of  vertebrate 
animals,  and  indeed  of  invertebrate 
animals  also,  he  found  full  confirmation 
of  his  view  that  the  sugar  of  the  liver  is 
not  supplied  directly  from  the  food,  but  is 
furnished  by  the  liver  itself,  through  a 
mechanism  analogous  to  that  of  secretion, 
at  the  expense  of  elements  of  the  blood 
which  traverse  the  hepatic  tissue.  He 
early  recognised,  however,  that  this 
hepatic  sugar,  though  it  did  not  come 
direct  from  the  food,  was  influenced  as 
regards  its  quantity  by  the  nature  of  the 
food.  Thus  he  observed  that  it  was  much 
diminished,  even  to  disappearance,  by  long 
starvation,  that  it  was  very  little  if  at 
all  increased  by  fatty  food,  but  was  very 
markedly  increased  by  gelatine  or  by  carbo- 
hydrates. This  influence  of  food  and  other 
influences  such  as  that  of  age,  as  well  as 
the    action    of    the    nervous    system,    he 

75 


CLAUDE    BERNARD 

more  fully  expounded  in  the  thesis  which 
he  maintained  for  his  Doctorate  in 
Science,  on  March  17,  1853,  and  which 
was  published  as  a  monograph  in  the 
same  year. 

In  the  course  of  these  researches  he  had 
come  upon  the  remarkable  fact  that  punc- 
ture of  the  fourth  ventricle  causes  temporary 
diabetes.  The  first  record  of  this  is  a  note 
communicated  to  the  Societe  de  Biologie,i 
in  which  the  author  stated  that  he  had 
previously  shown  the  same  effect  in 
rabbits  ;  no  published  account,  however, 
of  this  appears.  The  same  fact  was 
also  announced  in  a  brief  note  to  the 
Academie  des  Sciences. ^ 

It  is  interesting  to  note  the  way  in  which 
Bernard  was    led    to  this  striking    result. 

^  "  Compt.  Rend.  Soc.  Biol.,"  1849,  p.  60  (April), 
"  Cliiens  rendus  diabetiques." 

2  "  Compt.  Rend.,"  xxviii.  p.  393. 

76 


GLYCOGEN 

At  first  sight  it  has  the  appearance  of 
being  an  accidental  result  ;  and  the  fact 
that  so  early  as  February  3,  1849,1 
Bernard  had  stated  that  section  of  the 
cerebellar  peduncles  led  to  the  appearance 
of  albumin  and  sugar  in  the  urine,  lends 
a  certain  amount  of  support  to  this  idea. 
But,  according  to  Bernard  himself,  he  was 
led  to  it  by  a  process  of  reasoning. 

Regarding,  as  he  had  come  to  do,  the 
appearance  of  the  sugar  as  a  secretion — 
an  internal  secretion  of  the  liver — he 
argued  that  this  secretion,  like  other 
secretions,  would  be  subject  to  the  in- 
fluence of  an  appropriate  nerve.  Anato- 
mical considerations,  as  well  as  earlier 
observations  on  the  vagus,  and  its  relations 
to  digestion,^  led  him  to  suppose  that 
the    nerve    in     question    could    be    none 

^  "  Compt.  Rend,  de  la  Soc.  Biol.,"  184.9,  P-  H- 
2  "  Compt.  Rend.,"  xviii.,  1844,  p.  995,  Sec, 

77 


CLAUDE   BERNARD 

other  than  the  vagus  nerve.  And  he  was 
confirmed  in  this  view  by  the  fact  which 
he  had  early  ascertained  that  section  of  the 
vagus  nerves  did  away  with  the  formation 
of  the  sugar.  He  accordingly  expected  to 
find  that  galvanic  stimulation  of  the  vagus 
trunks  would  lead  to  an  increase  of  the 
hepatic  sugar  ;  but  in  this  he  was  griev- 
ously disappointed  ;  all  his  results  were 
negative.  Remembering,  however,  some 
older  experiments  of  his  on  the  fifth  pair, 
in  which  he  had  produced  secretory 
effects — tears  and  saliva — by  irritating 
the  nerve  in  a  special  way,  namely, 
by  puncturing  it  at  its  origin  in  the 
brain,  he  conceived  the  idea  of  applying 
the  same  method  to  the  vagus  at  its  origin 
in  the  floor  of  the  fourth  ventricle.  The 
experiment  succeeded,  the  sugar-producing 
or  glycogenic  function  of  the  liver  was 
thereby    highly  excited  ;    so    much   sugar 

78 


GLYCOGEN 

was  poured  so  rapidly  into  the  blood 
stream  that  it  could  not  be  disposed  of, 
and,  like  an  excess  of  sugar  in  the  blood 
produced  by  artificial  injection,  made  its 
way  into  the  urine.  Bernard  himself  was 
one  of  the  first  to  recognise  that  the 
theoretical  view  which  led  him  to  this 
remarkable  result  was  founded  on  error, 
that  the  vagus  is  not  the  channel  by  which 
the  influences,  started  by  the  puncture  of 
the  fourth  ventricle,  whatever  be  their 
nature,  reach  and  affect  the  liver,  that  the 
vagus  is  not  the  secretory  nerve  governing 
the  secretion  of  hepatic  sugar.  Never- 
theless the  wrong  view  led  him  to  an 
important  truth  ;  and  indeed  it  was  one 
of  Bernard's  characteristics  that  his  experi- 
mental search  after  new  facts  was  never 
a  haphazard  prodding  into  unknown 
ground  ;  he  was  always  guided  by  some 
preconceived  theory,  sometimes  right  but 

79 


CLAUDE   BERNARD 

more  often  perhaps  wrong.  No  less  a 
characteristic,  and  this  was  perhaps  the 
one  which  led  him  so  far,  was  his 
readiness  to  fasten  on  to  the  new  fact, 
and  to  consider  it  by  itself,  regardless 
of  the  theory  which  had  led  him  to 
it.  In  all  his  writings  he  insists  on  the 
value  of  imagination  and  preconceived 
theory  in  experimental  research  ;  but  he 
knew  how  to  use  them  and  when  to  throw 
them  on  one  side.  He  used  to  say  to 
those  who  were  working  with  them,  ''  Put 
off  your  imagination  as  you  take  off  your 
overcoat  when  you  enter  the  laboratory  ; 
but  put  it  on  again,  as  you  do  the  over- 
coat, when  you  leave  the  laboratory. 
Before  the  experiment  and  between  whiles 
let  your  imagination  wrap  you  round  ;  put 
it  right  away  from  yourself  during  the 
experiment  itself,  lest  it  hinder  your 
observing    power." 

80 


GLYCOGEN 

By  these  continued  observations,  con- 
firmed as  they  speedily  were  by  investi- 
gators elsewhere,  notably  by  Lehmann  in 
Leipzig,  though  criticised  and  controverted 
as  they  were  by  others,  more  especially 
perhaps  in  France  itself,  Bernard  had 
established  the  glycogenic  function  of  the 
liver  ;  he  had  proved  that  the  liver  pro- 
duces sugar  by  means  of  a  mechanism 
analogous  to  that  of  secretion  at  the 
expense  of  the  elements  of  the  blood 
traversing  the  hepatic  tissue. 

But  he  did  not  stop  here. 

He  soon  came  to  the  conclusion  that 
the  sugar  was  not  formed  at  one  step  out 
of  the  elements,  whatever  they  might  be, 
which  the  blood  brought  to  the  liver,  but 
that  the  sugar  came  from  some  substance 
existing  in  the  hepatic  tissue,  some  substance 
capable  of  being  converted  into  sugar, 
some   ''  glycogenic    substance."      He    was 

8l  G 


CLAUDE   BERNARD 

led  to  this  conclusion  in  the  following 
way. 

Taking  a  liver  fresh  from  the  body,  he 
sent  a  stream  of  water  through  it  until 
the  wash-water  issuing  by  the  hepatic 
vein  contained  neither  albumin  nor  sugar. 
He  washed  out  of  the  liver  all  the 
sugar  previously  present  in  it,  and  a 
decoction  of  the  liver  so  washed  out 
contained  no  sugar.  But  if  the  liver 
thus  washed  out  and  sugarless  were 
allowed  to  remain,  especially  in  a  warm 
place,  for  some  time,  say  for  a  few 
hours,  a  subsequent  stream  sent  through 
the  vessels  was  once  more  loaded  with 
sugar,  as  was  also  a  decoction  of  the  liver 
substance.  The  sugar  had  been  washed 
out  by  the  first  washing,  but  not  the  gly- 
cogenic substance,  and  this  latter  had 
subsequently  given  rise  to  fresh  sugar. 

He  next  found  that  the  conversion  of 
82 


GLYCOGEN 

this  glycogenic  substance  into  actual  sugar 
was   arrested   by  the    hepatic  tissue  being 
subjected   to    the    temperature   of   boiling 
water.     Aware  of  the    profound    changes 
which    proteid    matter     undergoes    when 
subjected    to   the    above    temperature,  his 
first   idea  was   that   his   "  glycogenic   sub- 
stance "  was  of  a  proteid  nature,  and  that 
its  conversion  into  sugar  was  prevented  by 
the  changes  of  composition  induced  in  it 
by  the    high    temperature.       But    he   was 
soon    set    right    by    the    observation    that 
a    decoction    of   boiled    liver,     though    of 
itself   it    remained  unchanged,    producing 
no  sugar,  readily  gave  rise  to  sugar  when 
a  small   quantity  of  an   infusion  of  fresh, 
unboiled  liver  was  added  to  it.     He  saw 
at  once   that  the  conversion   of   his    gly- 
cogenic   substance  was  brought    about  by 
a  kind   of  fermentation,   that   the  glyco- 
genic  substance   itself  was   of  the  nature 

83 


CLAUDE   BERNARD 

of  starch.  By  straining  the  liver  de- 
coction free  from  blood-vessels  and  con- 
nective tissue  elements,  he  was,  by 
subsequent  washing  with  alcohol  and 
ether,  able  to  prepare,  in  the  form  of  a 
dry  powder,  a  glycogenic  substance,  which, 
not  itself  giving  the  tests  for  dextrose, 
was  readily  converted  by  fermentation 
into  dextrose.  These  important  results 
he  communicated  to  the  Academie  des 
Sciences  on  Sept.  24,   1 855.1 

His  powdered  liver,  however,  was  still 
a  very  impure  substance,  and  it  was  not 
until  March  23,  1857,2  that  he  could 
describe  the  complete  isolation  by  the 
now  well-known  potash-alcohol  process, 
and  the  definite  characters  of  the  sub- 
stance   which    he     now    felt    justified    in 

^  "  Compt.  Rend.,"  xli.  p.  461,  "  Sur  le  mccha- 
nisme  de  la  formation  du  sucre  dans  le  foie." 

2  "  Compt.  Rend.,"  xliv.  p.  578,  "  Sur  le  median- 
isme,"  &c.,  (suite). 

84 


GLYCOGEN 

calling  glycogen.  He  obtained  this  in  a 
sufficiently  pure  form  to  enable  Pelouze, 
as  the  result  of  an  elementary  analysis,  to 
assert  its  carbohydrate  nature.  He  had, 
earlier  in  the  year,i  given  some  account 
of  these  results  to  the  Societe  de  Biologie ; 
and  it  may  here  be  mentioned  that 
Hensen^  had  independently  been  led  to 
accomplish  the  isolation  of  glycogen. 

In  the  above  memoir  Bernard  describes 
the  technique  for  the  extraction  and  puri- 
fication of  glycogen,  and  gives  an  account 
of  its  reactions,  including  that  towards 
iodine.  He  adds  some  valuable  reflections 
on  the  whole  subject,  pointing  out  that 
while  the  formation  of  glycogen  is  a  vital 
act,  that  is  to  say,  takes  place  only 
under  conditions  of  life,  the  conversion  of 
glycogen    into    dextrose,  by  a  process    of 

^  "Mem.  Soc.  Biol.,"  1857,  pp.  1-7. 
^  "Verhl.    d.    Phys.    Med.    Gesell.    Wurzburg," 
Bd.  viii.,  1856,  s.  219. 

85 


CLAUDE   BERNARD 

fermentation,  is  independent  of  life.  He 
calls  attention  to  the  fact  that  the  blood 
contains  in  itself  a  ferment  capable  of 
converting  glycogen  into  dextrose,  and 
suggests  that  the  nervous  system,  in  giving 
rise  to  an  increase  of  sugar,  as  in  the 
diabetic  puncture,  probably  acts  in  an 
indirect  manner  by  modifying  in  some 
way  the  circulation.  He  further  draws 
an  interesting  comparison  between  gly- 
cogen and  sugar  in  the  liver,  and  starch 
and  sugar  in  a  germinating  seed ;  in 
the  one  glycogen,  in  the  other  starch,  is 
formed  and  deposited  in  the  cell  by  virtue 
of  the  living  activities  of  the  tissue,  in 
both  the  carbohydrate  so  formed  is  con- 
verted into  sugar  by  the  action  of  a 
ferment. 

This  brings  to  a  close  the  first  chapter 
of  the  history  of  glycogen.  It  was 
Bernard's  good  fortune  not  only  to  have 

86 


GLYCOGEN 

begun  but  to  have  completed  the  dis- 
covery. Though  the  whole  investigation 
took  several  years  to  accomplish,  though 
from  the  very  outset  the  matter  ex- 
cited great  interest  throughout  the  whole 
scientific  world,  and  many  other  hands 
were  put  to  the  work,  it  was  Bernard 
himself  who,  following  steadfastly  the  lead 
given  by  his  initial  observation,  through 
successive  steps,  each  new  one  reached  by 
trials  based  on  sound  reasoning  suggested 
by  its  forerunner,  arrived  at  the  final  goal. 
Though  he  never  shrank  from  making 
known  each  new  result  as  he  came  upon  it, 
he  had  not  the  mortification,  which  some- 
times falls  to  a  pioneer,  of  seeing  his  leading 
conceptions  realised  by  experimental  proof 
in  the  hands  of  others  before  he  himself  has 
had  time  to  furnish  the  decisive  evidence. 
The  whole  story  lies  in  Bernard's  own 
writings.     To  the  account  which  he  gives 

87 


CLAUDE    BERNARD 

of  his  own  researches,  the  rest  of  contem- 
porary literature  on  the  subject,  whether 
we  consider  the  corroborative  writings  of 
Lehmann  and  others,  or  the  opposing  views 
offered  by  Figuier,  Sanson,  and  others, 
appears  as  a  mere  unimportant  fringe.  Nor 
can  much  importance  be  attached  to  the 
mere  fact  that  Hensen  was  prior  to  Bernard 
in  publishing  an  account  of  the  isolation  of 
glycogen,  since  Bernard  had  practically 
effected  the  isolation  some  time  before. 
Bernard  started  the  fox,  was  at  the  head  of 
the  pack  through  the  whole  run,  and  was 
first  in  at  the  death. 

Every  discovery  in  physiology  of  any 
marked  magnitude  has  a  double  bearing. 
On  the  one  hand,  it  is  a  link  in  a  chain,  or 
rather  a  network,  of  special  problems  ;  it 
serves  as  a  starting-point  of  new  inquiries, 
and  fills  up  gaps  in,  or  it  may  be  supplies 
corrections  to,  old  ones.  On  the  other  hand, 

88 


GLYCOGEN 

it  influences  more  or  less  deeply,  according 
to  its  nature,  general  physiological  concep- 
tions. Bernard's  discovery  of  the  glyco- 
genic function  of  the  liver  was  powerful  in 
both  these  directions.  As  a  mere  contribu- 
tion to  the  history  of  sugar  within  the 
animal  body,  as  a  link  in  the  chain  of 
special  problems  connected  with  digestion 
and  nutrition,  its  value  was  very  great. 
Even  greater,  perhaps,  was  its  effect  as  a 
contribution  to  general  views. 

The  view  that  the  animal  body,  in  con- 
trast to  the  plant,  could  not  construct, 
could  only  destroy,  was,  as  we  have  seen, 
already  being  shaken.  But  evidence,  how- 
ever strong,  offered  in  the  form  of  statis- 
tical calculations,  of  numerical  comparisons 
between  income  and  output,  failed  to  pro- 
duce anything  like  the  conviction  which 
was  brought  home  to  every  one  by  the 
demonstration  that  a  substance  was  actually 

89 


CLAUDE   BERNARD 

formed  within  the  animal  body  and  by  the 
exhibition  of  the  substance  so  formed. 

No  less  revolutionary  was  the  demon- 
stration that  the  liver  had  other  things  to 
do  in  the  animal  economy  besides  secreting 
bile.  This,  at  one  blow,  destroyed  the  then 
dominant  conception  that  the  animal  body 
was  to  be  regarded  as  a  bundle  of  organs, 
each  with  its  appropriate  function,  a  con- 
ception which  did  much  to  narrow  inquiry, 
since  when  a  suitable  function  had  once 
been  assigned  to  an  organ  there  seemed  no 
need  for  further  investigation.  Physiology, 
expounded  as  it  often  was  at  that  time,  in 
the  light  of  such  a  conception,  was  apt  to 
leave  in  the  mind  of  the  hearer  the  view 
that  what  remained  to  be  done  consisted 
chiefly  in  determining  the  use  of  organs 
such  as  the  spleen,  to  which  as  yet  no  defi- 
nite function  had  been  allotted.  The  dis- 
covery  of  the  glycogenic  function  of  the 

90 


GLYCOGEN 

liver    struck   a  heavy  blow  at   the   whole 
theory  of  functions. 

No   less   pregnant   of  future  discoveries 
was  the  idea  suggested  by  this  newly  found 
out  action  of  the  hepatic  tissue,  the  idea 
happily  formulated  by  Bernard  as  "internal 
secretion."    No  part  of  physiology  is  at  the 
present   day  being  more  fruitfully  studied 
than  that  which   deals  with   the    changes 
which  the   blood  undergoes    as   it  sweeps 
through  the  several  tissues,  changes  by  the 
careful  adaptation  of  which  what  we  call 
the  health  of  the  body  is  secured,  changes 
the  failure  or  discordance  of  which  entails 
disease.    The  study  of  these  internal  secre- 
tions constitutes   a  path  of  inquiry  which 
has    already    been    trod    with    conspicuous 
success,  and  which  promises  to  lead  to  un- 
told discoveries  of  the  greatest  moment  ; 
the  gate  to  this  path  was  opened  by  Ber- 
nard's work. 

91 


CLAUDE   BERNARD 

With  the  demonstration  of  the  actual 
substance  the  first  chapter  of  the  story  of 
glycogen  is,  as  we  have  said,  closed.  By  it 
the  mode  of  inquiry  was  profoundly  changed 
and  a  new  chapter  begun.  The  search  for 
indications  of  the  appearance  of  sugar  was 
replaced  for  a  search  for  the  substance 
glycogen.  And  Bernard  himself  was  the 
first  to  contribute  to  the  new  chapter.  He 
had  quite  early  in  his  investigation  come 
across  and  appreciated  the  importance  of 
the  fact  that  sugar  is  formed  in  the  liver 
of  the  embryo  after  a  certain  stage  of  intra- 
uterine life  and  that  sugar  is  present  in  the 
anmiotic  and  allantoic  fluids.  He  was  now 
armed  with  two  new  methods  of  inquiry. 
In  the  first  place,  he  could  quantitatively 
determine  the  amount  of  glycogen  present 
in  this  or  that  tissue  under  these  or  those 
circumstances  ;  this  gave  a  precision  to  his 
results   which  could  never  be  gained  by  a 

92 


GLYCOGEN 

mere  estimation  of  the  production  of  sugar. 
In  the  second  place,  he  early  recognised  that 
the  colour  reaction  of  glycogen  towards 
iodine,  the  port-wine  colour  which  glycogen 
showed  when  treated  with  iodine  under 
favourable  circumstances,  enabled  him  to 
study  the  ways  of  glycogen  not  only  by 
chemical  but  also  by  histological  investiga- 
tion, the  one  method  of  investigation  con- 
firming or  checking  the  other. 

In  purely  histological  inquiries  Bernard 
was  not  "  at  home  "  ;  but  in  the  micro- 
scopical search  after  glycogen  he  was  able 
to  avail  himself  of  the  skilful  help  of  a 
young  German  then  studying  under  him, 
one  who  was  already  becoming  knov/n 
by  a  remarkable  research  in  the  physiology 
of  muscle,  and  who  has  since  achieved  a 
foremost  place  among  the  physiologists  of 
the  day,  Willie  Kiihne,  the  distinguished 
professor   of  Heidelberg.     In   saying  that 

93 


CLAUDE   BERNARD 

Bernard  did  not  seem  to  have  the  same 
facility  in  histological  as  in  other  physio- 
logical inquiries,  this  must  be  understood 
to  apply  to  the  technique  only.  In  grasp- 
ing the  meaning  of  histological  facts,  he 
showed  the  same  quick  power  which 
characterised  him  in  all  his  work.  He, 
for  instance,  early  recognised  the  signi- 
iicance  of  the  granules  in  the  secreting 
cells  of  the  pancreas  ;  and  indeed  Kiihne, 
to  whom,  after  Bernard,  so  much  of  our 
knowledge  of  the  pancreas  is  due,  gave 
to  these  granules  the  name  of  "  Bernard's 
granules." 

The  fruits  of  the  new  method  he  made 
known  to  the  Academic  des  Sciences  in 
1 859.1  In  a  series  of  papers  he  gave 
an  account  of  the  presence  of  glycogen 
on  the  one  hand  in  the  maternal  pla- 
centa, and,  on  the  other  hand,  in  various 

^  "Compt.  Rend.,"  xlviii.  pp.  ']^^  673,  884. 
94 


GLYCOGEN 

foetal  tissues,  calling  attention  especially 
to  the  relatively  enormous  quantity  of 
glycogen  present  in  developing  striated 
muscles.  With  characteristic  breadth  of 
view  he  dwells  on  the  light  which  the 
presence  of  this  carbohydrate  in  tissues 
while  they  are  struggling  to  put  on  their 
appropriate  structure,  throws  on  the 
nature  of  the  processes  of  nutrition. 

This  may,  perhaps,  be  considered  as 
Bernard's  last  important  contribution  to 
the  history  of  glycogen.  He,  it  is  true, 
continued  to  work  on  the  subject  to 
the  end  of  his  life.  In  his  last  year, 
in  1877,  he  contributed  three  papers 
upon  it  to  the  Academie  des  Sciences, 
having  in  the  interval  between  that  and 
1859  published  other  papers,  and  more 
especially  made  known  the  results  of  fresh 
experiments,  and  developed  general  views 
in  his  lectures  delivered  at  the  College  de 

95 


CLAUDE   BERNARD 

France  and  elsewhere.  The  volume  of 
lectures  on  Diabetes  ("  Lemons  sur  le 
Diabete ")  published  in  1877  may  be 
considered  as  his  last  testament  touch- 
ing the  subject. 

All  these  later  writings,  however,  are 
chiefly  occupied  in  expounding  or  defend- 
ing his  views  on  the  nature  and  purpose 
of  the  glycogenic  function,  or  in  criticising 
the  opinions  on  the  same  subject  expressed 
by  others. 

Not  a  little  space  in  them  is  from  time 
to  time  devoted  to  a  severe  criticism  on 
what  he  called  the  vitalistic  view  put  for- 
ward by  some,  and  more  especially  by  his 
pupil  Pavy,  teaching  that  the  appearance  of 
sugar  in  the  liver  is  a  post-mortem  phe- 
nomena. Bernard,  as  we  have  seen,  had 
taken  up  a  definite  position  in  relation  to 
questions  of  so-called  ''  vitalism "  ;  and 
if  ever  he  was  tempted  to  abandon  the  tone 

96 


GLYCOGEN 

of  calm  and  dispassionate  attitude  in  which 
he  discussed  most  questions,  it  was  when 
he  had  to  deal  with  vitahstic  theories. 
His  very  last  paper  but  one,  that  in  the 
"Comptes  Rendus"  of  1877,  deals  tren- 
chantly with  this  view  of  the  post-mortem 
character  of  the  appearance  of  hepatic  sugar; 
and  in  his  lectures  on  Diabetes  he  cannot 
resist  the  temptation  to  be  sarcastic  when 
discussing  it,  pointing  out  that  according 
to  it  ''a  diabetic  patient  is  a  walking 
corpse  ;  a  truly  droll  idea." 

The  reader  who  reads  these  various  later 
writings  in  the  light  of  the  knowledge 
which  we  possess  to-day  cannot  but  be 
struck  with  the  reflection  that  if  we  put 
aside  the  discovery  of  share  taken  by  the 
pancreas  in  determining  the  part  played  by 
sugar  in  the  animal  body,  all  that  has 
since  been  added  by  others  to  Bernard's 
own  results,  amounts,  compared  with  them, 

97  H 


CLAUDE   BERNARD 

to  something  relatively  small.  It  has  rarely 
fallen  to  the  lot  of  any  one,  who  made  the 
beginning  of  such  a  wholly  new  line  of 
research,  to  carry  it  forward  so  far  towards 
completion  with  his  own  hands  ViS  Bernard 
did  the  glycogenic  function  of  the  liver. 
The  views  which  he  left  behind  him  in 
1877  have,  on  the  whole,  not  been  largely 
modified  by  subsequent  inquiry.  Much, 
for  instance,  has  been  done  since  that  in 
determining  the  influence  of  carbohydrate 
food  on  the  storage  of  hepatic  glycogen  ; 
but  it  is  worthy  of  notice  that  Bernard 
early  recognised  this,  and  that  in  spite  of 
the  fact  that  the  corner-stone  of  his  whole 
discovery  consisted  in  the  proof  that  sugar 
in  the  hepatic  vein  was  independent  of 
sugar  in  the  alimentary  canal. 

So  also  in  many  other  details  the  kernel 
of  what  we  are  discussing  to-day  may  be 
found     in     some    sentence     or    other    of 

98 


GLYCOGEN 

Bernard*s.  It  has  been  the  fate  of  many 
other  men  in  many  matters  to  have  merely 
laid  a  foundation  on  which  other  men  have 
built.  He,  in  the  matter  of  glycogen,  not 
only  laid  the  very  first  stone,  but  left  a 
house  so  nearly  finished  that  other  men 
have  been  able  to  add  but  little. 


99 


V 
Vaso-motor  Nerves 

THE  discovery  of  glycogen  was  Ber- 
nard's greatest  achievement ;  next 
in  importance  to  this,  and,  indeed,  hardly 
less  than  it,  was  his  discovery  of  the  vaso- 
motor system.  The  part  which  he  played 
in  this  latter  discovery,  however,  was  very 
different  from  that  which  he  played  in 
the  former.  As  we  have  just  said,  he 
not  only  began  but  carried  out  and,  we 
may  almost  say,  completed  the  discovery 
of  glycogen  by  his  own  researches  ;  the 
contributions  of  others  in  his  own  time 
were  almost  insignificant  as  compared  with 

100 


VASO-MOTOR   NERVES 

his.  He,  moreover,  at  the  very  outset 
grasped  the  full  and  almost  the  exact 
meaning  of  what  he  had  laid  hold  of. 

In  the  case  of  the  vaso-motor  nerves, 
it  was  others  rather  than  himself  who 
first  recognised  the  importance  of  his 
earlier  result,  the  vaso-motor  function  of 
the  cervical  sympathetic.  In  the  case  of 
this,  as  in  the  case  of  glycogen,  he  was 
looking  for  something  else  when  he 
found  it.  But,  unlike  his  attitude  in 
the  glycogenic  research,  he  did  not  at 
once  turn  aside  and  give  himself  up  to 
the  new  result.  It  would  almost  seem 
as  if  he  did  not  at  first  see  its  im- 
portance, and  v/as  inclined  to  continue 
on  the  line  of  inquiry  which  he  had 
originally  laid  out  for  himself;  and,  in- 
deed, to  this  he  clung  to  the  end,  though 
the  interest  which  others  manifested  in  the 
intercurrent    vaso-motor    phenomena    led 

lOI 


CLAUDE    BERNARD 

him,  in  spite  almost  of  himself,  to  develop 
this  part  of  the  inquiry. 

Before  proceeding  to  speak  of  Bernard's 
investigation,  it  will  be  well  perhaps  to  call 
to  mind  what  was  the  condition  of  our 
knowledge  at  that  time  of  the  relation  of 
the  nervous  system  to  the  blood-vessels. 

The  great  German  physiologist,  Johannes 
Miiller,  in  the  1838  edition  of  his  classical 
work  on  Physiology,  the  English  transla- 
tion of  which  by  Baily  appeared  in  1841 
and  1843,  recognises  two  kinds  of  muscle, 
the  striated  muscles,  the  muscles  of  the 
trunk  and  limbs,  and  the  non-striated 
muscles  of  organic  life  found  in  the  intes- 
tines, the  uterus,  the  bladder,  and  the  iris. 
He  also  describes  the  contractile  "cellular" 
or  ''  connective  "  tissue,  as  we  now  call  it  ; 
of  this  the  dartos  of  the  scrotum  serves 
as  his  characteristic  example.  He  dis- 
tinguishes this  from    muscle   by  the  fact 

102 


VASO-MOTOR   NERVES 

of  its  yielding  gelatine,  whereas  muscles, 
he  says,  are  fibrinous.  He  discusses  at 
great  length  the  question  whether  arteries 
possess  muscular  contractility,  and  de- 
cides firmly  in  the  negative  ;  they  possess 
physical  elasticity,  but  not  muscular  con- 
tractility. He  admits,  however,  the  possi- 
bility that  the  contraction  observed  in  small 
vessels  upon  the  application  of  cold,  as  in- 
sisted upon  more  especially  by  Schwann, 
may  be  a  manifestation  of  that  which  he,  in 
the  language  initiated  by  Bichat,  speaks  of 
as  "  insensible  organic  contractility,"  and 
which  was  supposed  to  be  the  basis  of  the 
*^  tonus  "  not  only  of  the  tissues  of  organic 
life,  but  even  of  the  skeletal  muscles. 
Miiller  obviously  was  wholly  unprepared 
for  vaso-motor  nerves,  even  within  a  few 
years  of  Bernard's  discovery  of  them. 

The  fact,  however,  that  the  sympathetic 
nerves  were  in  many  places  traced  to  blood- 

103 


CLAUDE   BERNARD 

vessels  was  leading  men  to  suspect 
that  the  nervous  system  must  in  some 
way  govern  the  blood-vessels.  In  1840 
Henle,  discoursing  on  the  physiology  of 
"  sympathy,"  and  putting  to  himself  the 
question  why  do  sympathetic  fibres, 
apparently  motor  in  nature,  go  to  such 
structures  as  arteries  if  these,  as  supposed, 
are  devoid  of  muscles,  was  led  to  the  con- 
clusion that  the  middle  coat  of  the  arteries 
is  really  in  part  muscular  in  nature,  though 
the  muscular  tissue  in  them  is  of  a  kind 
somewhat  different  from  that,  not  only 
of  the  skeletal  muscles,  but  also  of  such 
muscles  as  those  of  the  intestine.  And  in 
the  same  year  Stilling,  in  a  work  on  ''  Spinal 
Irritation,"  had  introduced  the  word  "vaso- 
motor." Arguing  on  theoretical  grounds 
he  had  come  to  the  conclusion  that  there 
were  motor  nerves  not  subject  to  the  will 
but  capable  of  being  put  into  action   by 

104 


VASO-MOTOR   NERVES 

sensory  impulses,  nerves  which  determined 
the  movements  of  the  blood,  and  which  he 
therefore  proposed  to  call  "  vaso-motor 
nerves." 

A  little  later  on  the  whole  question  of  the 
muscular  nature  of  the  blood-vessels  and 
other  allied  tissues  was  made  clear  through 
the  discovery  by  Kolliker  in  1 846  of  the 
fact  that  plain  muscular  tissue,  whether 
occurring  in  masses  or  in  a  scattered 
fashion,  was  made  up  of  minute  spindle 
shaped  cells  aggregated  together. 

The  way  was  now  open  for  the  clear 
proof  of  the  existence  and  action  of  vaso- 
motor nerves  ;  but  no  one  supplied  this 
until  Bernard  came  upon  it.  And  his 
discovery  was  made  in  this  way. 

He  proposed  for  himself  the  study  of 
the  influence  of  the  nervous  system  on 
animal  heat ;  and  he  began  by  attempting  to 
ascertain  in  an  exact  manner  how  far  the 

105 


CLAUDE   BERNARD 

temperature  of  a,  part  of  the  body  was 
affected  by  the  section  of  the  nerve  or 
nerves  distributed  to  it.  Of  the  three 
kinds  of  nerves,  at  that  time  distinguished 
from  each  other,  motor,  sensory,  and  sym- 
pathetic, he  began  with  the  sympathetic, 
being  led  to  this  choice  by  the  consideration 
that  the  sympathetic  fibres,  since  they  so 
often  accompany  the  blood-vessels,  are 
probably  specially  connected  with  the 
chemical  changes  between  the  blood  and 
the  tissue  which  determine  the  develop- 
ment of  heat  and  so  the  temperature  of 
the  part. 

Accordingly,  choosing  the  cervical  sym- 
pathetic as  a  sympathetic  nerve  easy  of 
access,  he  divided  that  nerve  in  the  neck. 
Holding  the  preconceived  idea  that  the 
influence  of  the  nerve,  if  any  such  existed, 
was  in  the  direction  of  bringing  about 
chemical    changes    involving    the    setting 

1 06 


VASO-MOTOR    NERVES 

free  of  heat,  he  expected  to  find  that  the 
section  of  the  nerve  by  removing  that 
influence  would  lead  to  a  lowering  of 
temperature.  To  his  surprise  he  obtained 
a  contrary  result.  When  in  a  rabbit  or 
other  animal  he  divided  the  cervical  sym- 
pathetic on  one  side  of  the  neck,  the 
temperature  of  that  side  of  the  head  and 
neck,  instead  of  falling,  rose,  the  rise  being, 
under  favourable  circumstances,  very  con- 
siderable, several  degrees  Centigrade,  and 
readily  appreciated  even  by  the  hand.  A 
similar  rise,  or  even  a  more  marked  one, 
followed  the  removal  of  the  suoerior 
cervical  ganglion  on  one  side.  At  the 
same  time  he  observed  an  increase  in  the 
sensibility  of  the  side  of  the  head  operated 
on  ;  and  the  title  of  his  first  communica- 
tion on  the  subject,  read  at  the  Societe  de 
Biologic  in  December,  1851,  was  ''In- 
fluence   du    grand    sympathique    sur     la 

107 


CLAUDE   BERNARD 

sensibilite  et  sur  la  calorification/'  A 
subsequent  communication  on  the  same 
subject  to  the  Academic  des  Sciences  on  the 
29th  of  March  of  the  following  year^  bears 
a  similar  title,  ''  De  I'influence  du  systeme 
nerveux  grand  sympathique  sur  la  chaleur 
animale."  Not  a  word  in  the  title  of 
either  paper  about  vascular  effects.  Yet  in 
both  papers,  though  they  are  very  short, 
he  describes  the  changes  in  the  blood- 
vessels. In  the  latter  he  says,  "  All  the 
part  of  the  head  which  becomes  hot  after 
the  section  of  the  nerve  becomes  also  the 
seat  of  a  more  active  circulation.  The 
arteries  especially  seem  fuller  and  appear  to 
pulsate  more  forcibly  ;  this  is  very  dis- 
tinctly seen,  in  the  case  of  the  rabbit,  in 
the  vessels  of  the  ear."  He  reserves 
for  further  consideration  the  question 
''  whether    the    vascular    changes   are    the 

I   "Compt.  Rend.,"  xxxiv.  p.  472. 
108 


VASO-MOTOR    NERVES 

cause  or  the   effect    of   the    rise    of   tem- 
perature." 

Bernard  published  the  account  of  this 
experiment  as  a  contribution  to  our  know- 
ledge of  animal  heat  ;  but  it  will  ever 
remain  as  the  first  clear  and  decided  ex- 
perimental proof  of  what  we  now  call  the 
vaso  -  motor  functions  of  the  nervous 
system.  I  say  "  the  first  clear  and  decided 
proof,"  for  not  only,  as  we  have  seen,  had 
previous  observers  drawn  inferences,  chiefly 
from  pathological  phenomena,  concerning 
the  influence  of  nerves  on  the  blood- 
vessels, but  vascular  changes  had  been 
observed  in  connection  with  the  cervical 
sympathetic  nerve  itself.  Thus  so  long 
before  as  1727  Pourfour  du  Petit  had 
observed  redness  of  the  conjunctiva  in  the 
dog  after  section  of  the  cervical  sympa- 
thetic, and  the  same  effect  had  been 
noticed   by  subsequent   observers,  such  as 

109 


CLAUDE   BERNARD 

Dupuy,  Brachet,  and  John  Reid.     But  the 
attention  of  these  and  other  inquirers  had 
been    almost    exclusively   concentrated    on 
the    remarkable    effects    of    the    cervical 
sympathetic    on    the    pupil  ;    in    watching 
the     constriction     of     the     pupil     which 
followed    section    of  the    cervical    sympa- 
thetic,  they    neglected    attendant    pheno- 
mena.    Even    in    the  remarkable  memoir 
by   Budge  and  Waller,   presented   to  the 
Academic  des  Sciences  in  the  same  year  as 
that  with  which  we  are  nov/  dealing,  1851, 
in  which   the    pupil-constricting   fibres  of 
the  cervical  sympathetic  are  traced  to  the 
spinal  cord,   and   in   preparing  which  the 
authors  must  have  repeatedly  come  across 
the  phenomena  to  which  Bernard  calls  atten- 
tion, there  is  nothing  which  can  be  con- 
sidered as  in  any  way  forestalling  Bernard's 
discovery.      They    were    looking    at    the 
pupil  and  saw,  so  to  speak,  nothing  else. 

no 


VASO-MOTOR   NERVES 

Indeed  Bernard  himself  tells  us  that 
from  the  very  beginning  of  his  experi- 
mental studies  in  1841,  he  had  repeatedly 
divided  the  cervical  sympathetic  without 
observing  the  phenomena  which  he  saw  for 
the  first  time  in  185 1.  In  these  previous 
experiments  his  attention,  Hke  that  of 
others,  had  been  directed  to  the  pupil  ; 
it  was  not  until  the  day  that  he  looked  for 
changes  in  the  face  and  ear  that  he  saw  them. 
He  was,  it  was  true,  looking  for  animal 
heat,  buf'he  saw  also  the  vascular  changes, 
saw  them  and  spoke  of  them  in  such  a  way 
that  never  afterwards  could  they  be 
ignored.  With  his  experiment  and  not 
with  any  of  those  made  by  his  forerunners 
does  our  knowledge  of  the  influence  of 
the  nervous  system  on  the  blood-vessels 
really  begin. 

That    Bernard's    observation    had    the 
significance  which  we  are  claiming  for  it 

III 


CLAUDE   BERNARD 

is  indeed  clear  from  the  fact  that  it  imme- 
diately attracted  great  attention  through- 
out the  whole  scientific  world.  Before 
August  of  the  same  year,  1852,  the  news 
of  it  had  crossed  the  Atlantic,  for  we 
find  Brown-Sequard,  then  sojourning  in 
America,  publishing  in  the  Philadelphia 
Medical  Examiner  of  that  month,  a  paper 
in  which  the  following  words  appear  : — 

"  I  have  found  that  the  remarkable 
phenomena  which  follow  the  section  of 
the  cervical  part  of  the  sympathetic,  are 
mere  consequences  of  the  paralysis  and 
therefore  of  the  dilatation  of  the  blood- 
vessels. The  blood  finding  a  larger  way 
than  usual,  arrives  there  in  greater  quan- 
tity ;  therefore  the  nutrition  is  more 
active.  Now  the  sensibility  is  increased 
because  the  vital  properties  of  the  nerves 
are  augmented  when  their  nutrition  is  aug- 
mented. ...  I   base  my  opinion  in  part 

112 


VASO-MOTOR   NERVES 

on  the  following  experiments  :  If  galvanism 
is  applied  to  the  superior  portion  of  the 
sympathetic  after  it  has  been  cut  in  the 
neck,  the  vessels  of  the  face  and  of  the 
ear  after  a  certain  time  begin  to  contract ; 
their  contraction  increases  slowly,  but  at 
last  it  is  evident  that  they  resume  their 
normal  condition,  if  they  are  not  even 
smaller.  Then  the  temperature  and  the 
sensibility  diminish  in  the  face  and  in  the 
ear,  and  they  become  in  the  palsied  side 
the  same  as  in  the  sound  side.  When  the 
galvanic  current  ceases  to  act,  the  vessels 
begin  to  dilate  again,  and  all  the  phe- 
nomena discovered  by  Dr.  Bernard  re- 
appear." 

Brown-Sequard  thus  supplied  what  we 
may  call  the  second  half  of  the  vaso-motor 
proof ;  and  it  will  be  observed  that  he  had 
none  of  Bernard's  hesitation  as  to  the 
interpretation    of   the    phenomena.       The 

113  I 


CLAUDE   BERNARD 

rise  of  temperature  as  well  as  the  increase 
of  sensibility  were  to  him  simply  the  effects 
of  the  greater  blood  supply,  due  to  the 
dilatation  of  the  vessels. 

A  little  later,  in  November  of  the  same 
year,  Bernard  quite  independently  of  and 
apparently  in  ignorance  of  Brown-Sequard's 
results  made  known  ^  that  galvanising  the 
upper  portion  of  the  divided  sympathetic 
produces  effects  diametrically  opposed  to 
those  of  section  ;  "  the  circulation  from 
being  active  becomes  feeble,  the  con- 
junctiva, the  nostrils,  and  the  ears,  which 
were  red,  become  pale."  He  therefore 
himself  also  supplied  the  second  half  of 
the  vaso-motor  proof. 

Still  a  little  later  Waller,  apparently 
ignorant  alike  of  both  Brown-Sequard's 
and  Bernard's  results,  announced  in  a 
communication  •   to     the     Academic     des 

^  "  C.  R.  Soc.  Biol.,"  1852,  p.  168. 
114 


VASO-MOTOR   NERVES 

Sciences  i  that  galvanism  of  the  cervical 
sympathetic  produced  constriction  of  the 
blood-vessels  of  the  head,  and  at  the 
very  same  time  Budge  ^  showed  that  the 
fibres  in  the  cervical  sympathetic  govern- 
ing the  blood-vessels,  like  the  fibres  for 
the  pupil,  took  origin  from  the  spinal 
cord. 

Up  to  this  time  all  Bernard's  communi- 
cations on  the  subject  had  been  extremely 
brief,  but  in  December  7th  and  21st  of 
1853,  he  read  a  longer  memoir  before  the 
Societe  de  Biologic,  3  in  which  he  more 
fully  developed  his  views.  It  is  worthy 
of  note  that  though  in  the  first  section, 
historical  In  nature,  of  this  paper,  he  states 
that  he  had  shown  that  galvanism  of  the 
upper   end    of  the  divided  cervical   sym- 

^  "  Compt.  Rend.,"  1853,  xxx\i.  p.  378,  dated 
Feb.,  1853. 

2  Ibid.,  p.  377. 

3  "  Memoires  de  la  Soc.  de  Biol.,"  1853,  p.  77. 


CLAUDE   BERNARD 

pathetic  "  caused  all  the  troubles  produced 
by  the  section  of  the  nerve  to  disappear," 
he  devotes  the  last  and  longest  section  to 
a  discussion  "on  the  relations  which  exist 
between  the  vascularisation  and  the  calori- 
fication of  the  parts  after  the  division  of  the 
great  sympathetic.''  In  this  section,  relying 
mainly  on  the  fact  that  when  the  circu- 
lation in  the  ear  is  arrested  by  ligature 
of  the  two  veins,  the  rise  of  temperature 
may  still  be  observed  upon  division  of  the 
sympathetic,  he  argues  that  "  the  increased 
warmth  cannot  be  explained  by  a  pre- 
tended paralysis  of  the  arteries  which,  by 
virtue  of  a  passive  enlargement  allow  a 
larger  quantity  of  blood  to  circulate."  And 
he  insists  on  the  fact,  as  indeed  he  did 
in  his  very  first  paper,  that  very  often 
on  the  day  after  the  section,  though  the 
vessels  have  returned  to  their  normal 
condition,   the   rise    of   temperature   per- 

ii6 


VASO-MOTOR   NERVES 

sists.  *'  In  a  word,"  he  concludes,  "  the 
vascular  phenomenon  which  follows  upon 
the  section  of  the  sympathetic  nerve  is 
active,  not  passive  ;  it  is  of  the  same 
nature  as  the  vascular  turgescence  which 
occurs  in  a  secreting  organ  on  its  pas- 
sage from  a  condition  of  rest  or  of 
feeble  activity  to  one  of  great  activity.'' 
Four  years  later,  in  a  lecture  at  the 
College  de  France  in  June,  1857,  he 
expounds  the  same  views,  employing  at 
times  the  very  words  of  his  original  com- 
munications ;  he  still  maintains  that  the 
vascular  phenomena  cannot  be  referred 
"  to  a  paralysis  pure  and  simple  of  the 
arteries."  In  this  lecture  it  may  be 
remarked  he  insists,  as  indeed  he  had 
done  in  his  earlier  communications, 
that  it  is  section  of  the  sympathetic 
fibre  alone  which  produces  a  rise  of 
temperature,     section     of     the      sensory 

117 


CLAUDE   BERNARD 

or  motor  fibre  giving  rise  to  a 
lowering  of  temperature  ;  the  rise  of 
temperature  which  is  observed  after  the 
section  of  a  mixed  nerve,  such  as  the 
sciatic,  is  due  to  the  sympathetic  fibres 
present  which  have  joined  the  nerve, 
peripheral  to  its  spinal  roots. 

In  Bernard's  mind  the  importance  of 
his  experiments  on  the  sympathetic  lay 
in  the  proof  which  they  afforded  that 
the  nervous  system  did  act  directly 
on  the  chemical  changes  in  the  tissues, 
and  so  intervened  in  the  develop- 
ment of  heat ;  the  vascular  phenomena 
he  regarded  as  of  secondary  impor- 
tance. Dwelling  on  the  fact,  which 
by  that  time  had  become  to  be  regarded 
as  established,  that  the  warmth  of  the 
blood  is  supplied  to  it  by  the  develop- 
ment of  heat  in  the  tissues  through  which 
it    passes,    rather   than   by   generation   of 

ii8 


VASO-MOTOR   NERVES 

heat  in  itself,  and  arguing  that  the  tissues 
of  the  face,  and  even  of  the  ear,  contribute 
to  the  blood  their  quota  of  heat  by- 
virtue  of  the  chemical  changes  going  on 
in  them,  he  was  inclined  to  think  that 
the  tissue  changes  formed  the  primary 
object  of  the  nerve  supply,  and  that  the 
vascular  changes  were  rather  the  effect 
than  the  cause  of  the  rise  of  temperature. 

He  was,  however,  himself  soon  led — and 
this  is  a  marked  instance  of  how  always  in 
his  inquiries  he  conscientiously  followed  the 
teaching  of  his  experimental  facts  in  spite 
of  his  preconceived  opinions — to  furnish 
an  instance  in  which  chemical  phenomena 
were  obviously  the  result  of  the  vascular 
changes,  and  at  the  same  time  to  make 
the  second  great  advance  in  our  know- 
ledge of  the  vaso-motor  system. 

In  the  very  first  scientific  paper  which 
he  published,  that  in  1841,  on  the  chorda 

119 


CLAUDE  BERNARD 

tympani,  Bernard  had  been  led  to  deny 
that  this  nerve  has  any  influence  over  the 
secretion  of  the  submaxillary  gland.  In 
the  very  same  year,  1851,  that  Bernard 
had  discovered  the  vaso-motor  functions 
of  the  sympathetic,  Ludwig  published  his 
classical  paper  on  the  secretory  functions 
of  the  chorda  tympani.  That  great  phy- 
siologist did  not,  however,  observe,  or 
at  least  did  not  describe,  any  of  the 
attendant  vascular  phenomena. 

In  the  January  of  1858,  Bernard,  work- 
ing on  the  submaxillary  and  other  glands, 
announced  to  the  Academie  des  Sciences  i 
that  when  a  gland  is  actively  secreting,  the 
blood  which  issues  from  it  along  the 
veins,  is  not  as  in  the  case  of  the  blood 
issuing  from  an  active  muscle,  dark  in 
colour,  but  is  bright  red,  in  fact  arterial. 
In    the    next  month,  in   a   short    commu- 

^  "Compt.  Rend.,"  xlvi.  p.  159. 
120 


VASO-MOTOR   NERVES 

nication  to  the  Societe  de  Biologie  i 
followed  by  a  longer  one  in  the  succeeding 
August  to  the  Academie  des  Sciences  2  he 
made  known  that  this  feature  of  the  venous 
blood  of  the  submaxillary  gland  only  ap- 
peared as  a  result  of  stimulation  of  the 
chorda  tympani  nerve  ;  when  the  other 
nerve  which  supplied  the  gland,  namely, 
the  sympathetic,  was  stimulated,  the  venous 
blood  issuing  from  the  gJand  was  dark, 
even  darker  than  usual.  The  gland  in  fact 
was  under  the  dominion  of  two  kinds  of 
nerves,  the  one  giving  rise  on  stimulation 
to  a  bright  and  the  other  to  a  dark  venous 
blood,  the  flow  in  the  former  case  being 
full  and  rapid,  in  the  latter  scanty  and 
slow.  He  showed  that  the  same  phe- 
nomena of  two  antagonistic  nerves  might 
be  observed  in  other  glands  ;  and  he  sup- 

'  "  Compt.   Rend,    de   la   Soc.  d.    Biol.,"   1858, 
P-  29.  ^  "Compt.  Rend.,"  xlvii.  p.  245. 

121 


CLAUDE   BERNARD 

plied  the  true  explanation  of  the  phenomena. 
He  argued  that  the  bright  red  arterial 
colour  of  the  venous  blood  issuing  from 
the  gland  upon  stimulation  of  the  chorda 
and  the  dark  colour  of  the  same  blood  when 
the  sympathetic  is  stimulated  could  not  be 
due  to  the  direct  action  of  the  nerves  on 
the  blood  ;  "  there  must  be  intermediate 
conditions,  and  these  are  supplied  by  the 
different  mechanical  modifications  brought 
about  in  the  capillary  circulation  by 
the  two  nerves  respectively."  The 
chorda  tympani  dilates  the  vessels,  and 
brings  about  so  rapid  a  circulation  that 
the  blood  has  not  time  to  lose  its  arterial 
colour  in  passing  through  the  capillaries. 
The  sympathetic  constricts  the  vessels, 
impedes  and  slackens  the  flow,  and  so 
permits  the  gaseous  exchange  to  be  exag- 
gerated. **  The  sympathetic  nerve  is  the 
constrictor  nerve  of  the  blood-vessels  ;  the 

122 


VASO-MOTOR   NERVES 

tympanico-lingual  (chorda  tympani)  is  their 
dilatator." 

This  is  the  first  announcement,  this  is 
the  statement  of  the  discovery,  of  vaso- 
constrictor and  vaso-dilator  nerves. 

To  Claude  Bernard,  then,  we  owe  the 
foundations  of  our  knowledge  of  the 
vaso-motor  system.  He  made  known 
to  us  the  existence  of  vaso-motor  nerves, 
and  he  also  made  known  to  us  that 
vaso-motor  nerves  are  of  two  kinds, 
vaso-constrictor  and  vaso-dilator.  These 
are  the  two  fundamental  facts  of  vaso- 
motor physiology  ;  all  else  supplied  by 
many   others   is  built  up   on   these. 

It  is  also  worthy  of  note,  as  indicative  of 
the  spirit  of  the  true  inquirer,  that  Bernard 
came  upon  both  these  truths  while  he  was 
in  each  case  looking  for  something  else. 
In  his  research  on  the  sympathetic,  his 
mind  was  fastened  on  the  relation  of  the 

123 


CLAUDE   BERNARD 

nerves  to  animal  heat ;  in  his  research  on 
the  submaxillary  gland  he  was  trying  to 
make  out  the  differences  in  the  colour  of 
the  venous  blood  according  as  the  gland 
was  active  or  at  rest.  In  each  case  he  had 
the  genius  to  appreciate  the  value  of  the 
new  truths  which  thus  incidentally,  as  it 
were,  came  to  the  surface.  A  more 
ordinary  observer,  with  his  mind  bent 
solely  on  his  main  theme,  might  have 
neglected  these  so  to  speak  side  issues. 
It  was  Bernard's  characteristic,  and  the 
secret  of  his  success  as  an  inquirer,  that 
he  was  ever  ready  to  turn  aside  and  grasp  a 
truth  thus  presenting  itself  by  the  way. 

Though  Bernard  admitted,  and  indeed 
himself  supplied  the  mechanical  explanation 
of  the  change  in  colour  of  the  blood  as  the 
mere  result  of  the  widening  or  narrowing 
of  the  arteries,  he  never  even  up  to  the 
end  abandoned  the  position  which  he  had 

124 


VASO-MOTOR   NERVES 

at  the  first  taken  up,  that  the  rise  of  tem- 
perature   which    follows    section     of    the 
sympathetic   fibres  is  not  to  be  explained 
as    the  mere  result  of  the  fuller  rush  of 
blood  through  the  widened  blood-vessels. 
He  insisted  to  the  last,  that  there  was,  or 
that  there  might  be,  a  direct  action  of  the 
nerve  on  the  tissues  changes  which  formed 
the  local  source  of  heat.  In  his  "  Lemons  sur 
la  chaleur  animale, "  delivered  in  1872,  but 
published  in  1876,  little  more  than  a  year 
before  his  death,  we  find  expressions  of  his 
views  on  this  question  cropping  up  from 
time  to  time.   Thus,  p.  222,  *' The  calorific 
phenomena  depend  on  actions  of  two  kinds, 
on  a  vascular  action  and  on  a  concomitant 
chemical  action."      Again,  p.  288,    '*The 
nervous  system  seems  at  first  sight  to  bring 
about  calorification  only  by  the  interven- 
tion of  the  circulation.      It  is  to  a  vaso- 
motor action  alone  that  one  at  first  refers 

125 


CLAUDE   BERNARD 

the  modification  of  animal  heat.  Although 
this  may  be  true  to  a  certain  extent,  we 
cannot,  however,  consider  it  as  an  adequate 
cause,  we  cannot  refuse  to  admit  an  action 
of  the  sympathetic  different  from  a  purely 
vaso-motor  action,  an  action  which  has  for 
a  result  a  local  increase  of  activity  in  the 
chemical  changes  of  the  tissues  attended  by 
a  direct  production  of  heat.  It  is  not  only 
by  dilating  the  vessels,  by  increasing  the 
local  circulation,  by  bathing  the  tissues  more 
fully  with  hot  blood,  that  the  section  of  the 
sympathetic  brings  about  a  rise  of  tem- 
perature ;  it  acts  also  by  increasing  the  local 
combustions  or  chemical  metabolism.  The 
vaso-motor  action  is  accompanied  by  a 
chemical  action  on  the  nutrition  of  the 
tissues.  .  .  .  Conversely,  it  is  not  only 
because  it  constricts  the  blood-vessels 
that  the  galvanisation  of  the  sympathetic 
produces  cold,  it  is  because  it  checks  and 

126 


VASO-MOTOR   NERVES 

slows  at  the  same  time  the  chemical  move- 
ment of  nutrition.  So  long  as  one  looks 
upon  the  lowering  of  temperature  as  the 
result  simply  of  the  constriction  of  the 
vessels,  one  may  confine  oneself  to  speaking 
of  the  sympathetic  as  a  constrictor  nerve 
of  the  blood-vessels.  But  if  one  admits,  as 
I  do,  the  independence  of  the  two  effects,  a 
special  name  is  wanted  for  each.  One  must 
say  that,  apart  from  its  vaso-motor  action, 
the  sympathetic  exerts  a  thermic  influence. 
Stimulation  of  it  produces  a  frigorific  effect ; 
section  or  paralysis  of  it  produces  a  calorific 
effect.  It  is  not  only  a  constrictor  nerve 
of  the  vessels,  it  is  also  a  frigorific  nerve." 
Again,  p.  443,  dealing  with  fever  he  says  : 
*'  The  phenomena  of  nutrition  are  of  two 
kinds  :  the  one  kind  is  that  of  destruction, 
of  splitting  up,  of  material  disorganisation 
or  combustion  ;  the  other  is  of  organisation 
or    organic   synthesis."       The  latter  phe- 

127 


CLAUDE   BERNARD 

nomena  are  under  the  influence  of  frigorific 
nerves  which  belong  more  especially  to  the 
sympathetic  system  ;  the  phenomena  of 
combustion  are  more  specially  governed  by 
the  vaso-dilator  or  calorific  nerves  which 
belong  more  particularly  to  the  cerebro- 
spinal system.  "  Now  fever  is  essentially 
an  exaggeration  of  the  action  of  the 
calorific  nerves  and  not  merely  a  paralysis 
of  the  vaso-constrictor  nerves." 

It  is  almost  impossible  to  exaggerate 
the  importance  of  these  labours  of  Bernard 
on  the  vaso-motor  nerves,  since  it  is  almost 
impossible  to  exaggerate  the  influence 
which  our  knowledge  of  the  vaso-motor 
system,  springing  as  it  does  from  Bernard's 
researches  as  from  its  fount  and  origin, 
has  exerted,  is  exerting,  and  in  widening 
measure  will  continue  to  exert,  on  all  our 
physiological  and  pathological  conceptions, 
on   medical  practice,  and  on  the  conduct 

128 


VASO-MOTOR    NERVES 

of  human  life.     There  Is  hardly  a  physio- 
logical  discussion  of  any  width  in   which 
we  do  not  sooner  or  later  come  upon  vaso- 
motor questions.     Whatever  part  of  phy- 
siology we    touch,  be  it    the  work   done 
by  a  muscle,  be   It  the  various   kinds  of 
secretive  labour,  be  It  the  insurance  of  the 
brain's  well-being  in  the  midst  of  the  hydro- 
static vicissitudes  to  which  the  change  of 
daily  life  subject  it,  be  it  that  maintenance 
of  bodily  temperature  which  is  a  condition 
of  the  body's   activity  :  in  all  these,  as  in 
many   other   things,   we   find   vaso-motor 
factors  intervening.      And  if,  passing  the 
insecure  and    wavering   line    which    parts 
health  from  illness,  we  find  ourselves  deal- 
ing with   inflammation  or   with   fever,  or 
with  any  of  the  disordered   physiological 
processes  which  constitute  disease,  we  shall 
find,  whatever  be  the  tissue  specially  affected 
by  the  morbid  conditions,  that  vaso-motor 

129  It 


CLAUDE   BERNARD 

influences  have  to  be  taken  into  account. 
The  idea  of  vaso-motor  action  is  woven 
as  a  dominant  thread  into  all  the  phy- 
siological and  pathological  doctrines  of 
to-day  ;  attempt  to  draw  out  that  thread 
and  all  that  would  be  left  would  appear  as 
a  tangled  heap. 

All  this  dominant  knowledge  has  come, 
as  does  a  full  stream  from  the  spring 
which  is  its  source,  from  Bernard's  initial 
experiment  on  the  cervical  sympathetic. 
This  is  one  of  not  a  few  instances,  in 
which  a  simple  experiment  on  a  living 
animal,  has  brought  suddenly  a  great 
light  in  a  field  where  men  had  been 
groping  in  vain  with  the  help  of  mere 
clinical  observations.  Before  this  simple 
experiment  attention  had  again  and  again 
been  drawn  to  cases  in  which  there  seemed 
to  be  some  connection  between  vascular 
changes    and    affections    or    conditions   of 

130 


VASO-MOTOR    NERVES 

nerves  ;  but  in  none  of  these  did  there 
come  to  light  any  clear  teaching  as  to 
what  that  connection  really  was  ;  all  was 
uncertain  and  obscure.  The  result  of 
the  experiment  was  the  first  clear  light 
which  broke  upon  the  subject ;  and  it 
was  the  following  up  of  the  teaching  of 
the  experiment  which  supplied  the  inter- 
pretation of  the  hitherto  obscure  clinical 
facts. 

And  it  may  be  well  here  to  insist 
that  the  experiment  in  question  was  what 
is  called  a  vivisectional  experiment — an 
experiment  which  Bernard,  had  he  lived 
in  this  country  and  in  our  day,  might 
have  been  prevented  from  doing  ;  his 
work  might  thus  have  been  strangled 
at  its  very  birth.  Some,  in  whom  senti- 
ment is  stronger  than  knowledge,  are  fond 
of  declaring  that  all  such  experiments  are 
useless  and  needless,  since  the  knowledge 


CLAUDE   BERNARD 

gained  by  them  might  be  come  at  in  other 
ways.  The  unbiassed  inquirer  in  the 
genesis  of  scientific  truths  and  conceptions 
may  be  ready  to  admit  that  in  the  course 
of  time  experiments  of  Nature's  making, 
not  of  man's,  might  have  suggested  to 
some  quick  mind  that  nerve-fibres  act  on 
blood-vessels,  and  might  even  have  hinted 
how  they  act.  And  haply  to  the  same 
quick  mind,  or  to  others  following  after 
him,  duly  impressed  with  what  had  been 
thus  suggested,  there  might  afterwards 
at  some  time  or  other,  by  fortunate 
occurrence,  have  come  other  like  experi- 
ments of  Nature  confirming  the  suggestion 
and  establishing  it  as  a  proved  truth.  The 
unbiassed  inquirer  will  admit  this  ;  but  he 
will  also  acknowledge  that  up  to  the  day 
of  Bernard's  experiment  all  the  experi- 
ments which  a  seemingly  cruel  Nature  had 
carried  out  year  after  year,  and  day  after 

132 


VASO-MOTOR    NERVES 

day,  on   suffering  mankind   and  suffering 
animals,  passed  before  the  eyes  of  observer 
after  observer,  quick   to  see  and  eager  to 
note,  without    suggesting   anything   more 
than    the    dimmest    and    shadowest    ideas 
of  such  an  action  of  nerve-fibre  on  blood- 
vessel.    And  he  will  also  admit  that  one 
stroke     of    Bernard's    knife  —  a     stroke 
bringing    a    pain     which     shrinks    to    a 
vanishing  point  compared    with    the   pain 
which  it  has  been  the  means  to   spare — 
laid  bare  a  truth,  which  all  Nature's  cruel 
strokes  had  during  long  years  been  unable 
to  bring  to  light. 

During  the  latter  half  of  the  century 
which  is  drawing  to  its  close,  the  power 
of  the  healer  to  cure  or  lessen  disease, 
and  to  prevent  or  soften  pain,  has  grown 
with  a  swiftness  which  is  in  a  measure 
marvellous,  and  that  in  spite  of  the  great 
helplessness   which  is    still   all    too    often 

^33 


CLAUDE   BERNARD 

witnessed.  That  power  is,  as  we  have 
just  said,  in  part  the  outcome  of  truer, 
wider  views  of  vaso-motor  action ;  and 
whatever  we  may  say  about  the  might 
have  been,  there  remains  the  plain  histori- 
cal fact  that  those  wider,  truer  views  have 
had  their  origin  in  Bernard's  initial  experi- 
ment on  a  living  animal. 


134 


VI 

Other  Discoveries 

THE  discoveries  of  glycogen,  of  vaso- 
motor nerves,  and  of  the  action  of 
the  pancreatic  juice  form  Bernard's  greatest 
claims  to  fame ;  but  he  also  enriched 
physiology  with  a  large  number  of  results, 
of  value  less  than  that  of  any  of  the  above, 
though  of  varied  importance.  We  need 
dwell   on   two   or  three  of  these  only. 

In  the  quite  early  years  of  his  career  he 
just  missed  the  opportunity  of  associating 
his  name  with  a  discovery,  the  influence 
of  which  on  the  progress  of  physiology 
has  been  not  much  less  than  that  of  the 

135 


CLAUDE   BERNARD 

discovery  of  glycogen  or  that  of  the  dis- 
covery of  vaso-motor  nerves. 

If  the  views  accepted  and  expounded  by 
physiologists  at  the  present  time,  especially 
perhaps  those  relating  to  the  actions  taking 
place  within  the  central  nervous  system,  be 
analysed,  it  will  be  found  that  the  doctrine 
of  inhibition  plays  a  very  important  part. 
It  is  not  less  dominant,  it  is  perhaps  even 
more  dominant,  in  pathological  views,  and 
in  the  application  of  physiology  to  medical 
practice.  Now  the  doctrine  of  inhibition 
had  its  origin  in  an  experiment  made  known 
by  the  brothers  Ernst  Heinrich  and  Eduard 
Friedrich  Weber  orally,  at  Naples,  in  the 
fall  of  1845,  ^^^  ^y  i^eans  of  print  in 
1 846  ;  the  experiment,  namely  (now  so 
well  known),  of  the  stoppage  of  the 
heart's  beat  by  stimulation  of  the  vagus 
nerve.  That  experiment,  which  still  re- 
mains the    typical    inhibition    experiment, 

13^ 


OTHER   DISCOVERIES 

was  the  first  clear  proof  that  a  nervous 
impulse,  instead  of  giving  rise  as  in  many, 
and  indeed  in  ordinary  cases,  it  does, 
to  an  expenditure  of  energy,  may  check 
expenditure  and  by  banking  up  energy 
increase  in  this  tissue  or  in  that  the 
potential  store.  It  has  been  the  starting- 
point  of  a  clearer  insight  into  the  molecular 
changes  of  the  tissues,  and  into  the  mode 
of  working  of  the  nervous  system. 

Now  in  1 846,  in  the  very  same  year  in 
which  the  brothers  Weber  published  their 
discovery,  Bernard  had  quite  independ- 
ently come  upon  the  same  result.  He 
himself  tells  us  ^  that  in  that  year  he 
ausculted  a  dog  while  the  vagus  nerve 
was  being  stimulated,  and  that  he  "  ob- 
served with  the  greatest  ease  that  at 
every  galvanisation  the  heart  stopped  and 
the  sound  ceased,  recurring  again  so  soon 

^  "  Le9ons  sur  le  systeme  nerveux,"  ii.  p.  381. 


CLAUDE   BERNARD 

as  the  galvanism  was  removed."  He 
mentioned  the  result  in  his  private  courses, 
and  it  was  published  by  one  of  his  pupils, 
a  Dr.  Lefevre,  in  a  thesis  which  appeared 
in   1848. 

But  Bernard  never  grasped  the  real 
bearing  of  the  result  which  he  thus 
observed.  Though  he  returned  to  the 
subject  in  a  communication  to  the  Societe 
de  Bioiogie  in  1 849  ^  he  never  followed  it 
up  ;  and  indeed,  though  in  his  lectures  on 
the  nervous  system,  as  well  as  in  his  later 
writings,  he  expounds  or  refers  to  the 
facts  of  inhibition,  these  never  seem  to 
have  largely  or  deeply  occupied  his 
thoughts,  never  tempted  him  on  to  spe- 
culations as  to  the  nature  and  mode 
of  action  of  inhibition,  such  as  have 
largely  exercised  the  minds  of  many  Ger- 
man and  other  physiologists.  Indeed,  so 
^  "  C.  R.  de  la  Soc.  de  Biol.,"  1849,  p.  13. 


OTHER   DISCOVERIES 

late  as  1858,  he  speaks  of  the  stoppage  of 
the  heart  by  the  vagus  as  "  a  singular 
experiment  of  which  several  interpretations 
and  explanations  have  been  offered." 

Bernard  was  very  early  attracted  to  the 
study  of  poisons.  He  recognised  in  them, 
as  he  himself  has  said,  physiological  in- 
struments of  greater  delicacy  than  the 
mechanical  means  at  the  disposal  of  the 
physiologist,  instruments  capable  of  ana- 
lysing, of  dissecting  as  it  were,  the 
anatomical  elements  of  the  body  while 
this  is  yet  alive.  He  looked  upon  them 
as  true  "vital  reagents."  Studying  them 
from  this  point  of  view,  rather  than  with 
the  desire  to  compile  the  complete 
toxicological  or  physiological  history  of 
any  one  of  them,  he  was,  on  the  one 
hand,  led  to  important  general  phy- 
siological conclusions,    and,    on  the   other 

139 


CLAUDE   BERNARD 

hand,  enriched  his  science  with  valuable 
new  methods  of  inquiry.  His  success  in 
this  direction  was  conspicuous  in  the  case 
of  curare  and  carbonic  monoxide. 

Curare,  otherwise  spelt  as  urari,  and  in 
many  other  ways,  an  arrow  poison  of  the 
South  American  Indians,  was  first  brought 
to  Europe  by  Sir  W.  Raleigh  from  Guiana 
in  1595.  It  had  been  described  by  many 
authors,  its  botanical  origin  and  its  general 
chemical  features  had  been  studied,  and 
several  authors  including  Brodie  the  great 
English  surgeon,  and  Charles  Waterton, 
the  traveller,  had  experimented  with  it. 
But  Bernard  was  the  first  to  analyse  with 
accuracy  its  physiological  action. 

He  tells  us  that  in  1 844  he  received  from 
his  friend  Pelouze,  a  supply  of  the  poison, 
being  some  which  Goudat  had  brought 
over  from  Brazil,  and  immediately  began 
to  experiment  with  it.     He  did  not,  how- 

140 


OTHER   DISCOVERIES 

ever,  publish  anything  of  the  results  which 
he  had  obtained  until  1850,  in  which 
year  he  made  a  communication  to  the 
Academie  des  Sciences  on  October  1 5  i  and 
to  the  Societe  de  Biologie  in  December.^ 
In  the  former  longer  paper  he  hardly  says 
more  than  that  the  poison  kills  rapidly  with- 
out convulsions  and  at  once  renders  the 
nerves  inexcitable  ;  he  does  not  distinguish 
between  different  kinds  of  nerves,  in  respect 
to  its  action  ;  and  indeed  the  greater  part 
of  the  paper  is  taken  up  in  showing  that 
the  poison  does  not  diffuse  from  the  inte- 
rior of  the  alimentary  canal  into  the  blood, 
and  hence  is  harmless  when  swallowed, 
though  a  minute  quantity  introduced  into 
a  wound  is  rapidly  fatal.  In  the  second 
communication  he  says  that  the  poison 
abolishes  reflex  actions,  destroying  rapidly 

^  "Compt.  Rend.,"  xxxi.  p.  533. 
^  "  C.  R.  de  la  Soc.  de  Biol.,"  1850,  p.  195. 

141 


CLAUDE   BERNARD 

and  completely  the  motor  and  sensory 
properties  of  the  nervous  system ;  and  he 
especially  insists  that,  while  it  at  once  renders 
the  nerves  inexcitable,  it  leaves  the  muscles 
fully  excitable,  in  this  respect  affording  a 
marked  contrast  to  nicotine,  which  des- 
troys the  irritability  of  the  muscles  and  in 
causing  death  brings  about  convulsions. 
This  marked  effect  on  the  nerves  in  the 
absence  of  any  effect  on  the  muscles  was 
recognised  by  Bernard,  and  perhaps  even 
more  distinctly  by  others,  as  a  convincing 
proof  of  the  correctness  of  the  view  that 
the  irritability  which  muscular  tissue  dis- 
plays is  an  independent  property  of  its 
own,  and  not  merely  one  conferred  on  it 
by  the  nervous  tissue  supplying  it,  a 
matter  which  at  the  time  served  as  the 
occasion  of  lively  controversy. 

From  1850  to  1856,  Bernard  published 
no    formal     account    of     the     researches 

142 


OTHER   DISCOVERIES 

which  he  continued  to  make  on  curare, 
but  from  his  paper  communicated  to  the 
Academie  des  Sciences  in  1856  ^  as  well 
as  from  his  "  Lemons  sur  les  efFets  des 
substances  toxiques,"  published  in  1857, 
we  learn  that  already  in  1852  he  had 
arrived  at  and  made  known,  appa- 
rently in  his  lectures  at  the  College  de 
France,  further  remarkable  results,  which 
in  the  succeeding  years  he  continued  to 
extend  and  complete. 

In  1852,  having  observed  that  the 
muscles  of  a  frog  poisoned  with  curare  so 
far  from  being  less  irritable,  seemed  to  be 
more  irritable,  than  normal  muscles,  and 
being  aware  that  the  individual  differences 
existing  between  frogs  rendered  the  com- 
parison of  the  muscles  of  one  frog  with 
those  of  another  more  or  less  inexact,  and 
at  least  inconclusive,  he  was  led  to  make  a 
^  "Compt.  Rend.,"  xliii.  p.  825. 

H3 


CLAUDE   BERNARD 

comparative  experiment  on  the  muscles  of 
one  and  the  same  animal,  by  tying  the 
blood-vessels  of  one  leg,  so  as  to  shut  off 
the  blood  stream  from  the  tissues  of  that 
leg  before  he  introduced  the  curare  into 
the  circulation.  He  found  his  views 
corroborated  ;  the  muscles  in  the  leg 
supplied  with  blood  and  so  with  poison, 
were  more  irritable  to  direct  elec- 
tric stimulation  and  remained  so  for  a 
longer  time  than  did  the  muscles  in  the 
leg  from  which  the  blood  and  therefore 
the  poison  had  been  cut  off  by  the  liga- 
ture. But  in  making  the  experiment  his 
attention  was  arrested  by  another  fact,  that 
the  leg,  protected  from  the  curare  by  the 
ligature  not  only  remained  sensitive,  so  that 
it  was  moved  when  it  was  stimulated,  but 
also  that  movements  took  place  in  it  when 
the  skin  in  the  parts  of  the  body  to  which 
the  poison' had  had  access  were  stimulated  ; 

144 


OTHER  DISCOVERIES 

that    is    to    say,  stimulation    of   the    skin, 
which    produced    no    reflex   action   in  the 
poisoned  moiety  of  the  body,  could  bring 
about  by  reflex  action  movements  of  the 
muscles  -in    the    unpoisoned    leg.     He    at 
once  ^grasped  the  meaning  of  this,  namely, 
that    while    motor    nerves    were    rendered 
inactive  by  the  poisons,  the  sensory  nerves 
and  the  central  nervous  system  remained 
intact.      Here  again  we  have  an  instance 
of  how  Bernard's  genius  led  him  to  turn 
aside  from  an  inquiry  which  he  had  begun 
in  order  to  follow  up  a  hint  which,  as  it 
were,  accidentally  presented  itself.     When 
he    made    the    experiment    his    mind    was 
wholly   directed   towards  the   influence  of 
curare  upon  the  muscles  ;  but  he  at  once 
left  these  to  seize  upon  the  new  fact  con- 
cerning nerves,  which  had  always  escaped 
him    in    his    previous    observations.     By 
similarly    devised    experiments,    now    the 

145  L 


CLAUDE   BERNARD 

common  demonstrational  experiments  of 
the  lecture  room  and  the  laboratory,  he 
supplied  proof  that  curare  acts  upon  the 
motor  nerves,  the  abolition  of  their  func- 
tions being  peripheral,  not  central,  and  that 
not  only  the  motor  nerves  to  the  skeletal 
muscles,  but  other  efferent  nerves,  such 
as  the  vagus  fibres  to  the  heart,  are  by  an 
adequate  dose  of  the  poison  similarly  para- 
lysed. 

This  fundamental  fact  he  had  observed  so 
early  as  1852,  but  in  this  case  as  in  so  many 
others  he  did  not  rush  forward  to  publish 
it.  In  contrast  to  many  of  his  own  time  and 
since  he  had  a  dread  of  making  known  any 
new  result,  however  important  and  sure  it 
might  seem,  until  he  had  had  opportunity  to 
work  the  matter  thoroughly  out.  Indeed 
he  complains  of  how  against  his  will  he  at 
times  gave  to  the  world  a  discovery  in  an  un- 
finished condition,  because  the  insufficiency 

146 


OTHER   DISCOVERIES 

of  his  laboratory  and  of  other  means  of  ex- 
perimenting left  him  no  hope  of  perfecting 
it  as  he  desired.  "  I  am  only  too  familiar 
with  the  regrets  of  the  investigator  who, 
simply  by  reason  of  the  lack  of  material 
means  is  prevented  from  carrying  out  the 
experiments  which  he  has  devised,  and  is 
driven  to  abandon  researches  which  he  has 
in  his  head  and  is  led  to  make  known  a 
discovery  while  it  is  as  yet  a  mere  rough 
sketch,  not  a  completed  work."i  It  was  not 
until  1856  that  he  gave  a  formal  account  of 
what  he  had  discovered  four  years  before ; 
and  he  was  led  to  speak  then  because 
Kolliker  at  Wiirzburg,  in  that  year  pub- 
lished a  paper  showing  that  he  had  inde- 
pendently arrived  at  the  same  main  results. 
The  priority  however  clearly  belongs  to 
Bernard,  though  Kolliker's  investigation 
was  in  some  respects  more  complete  and 
^   "  Physiologic  generale,"  p.  209. 

H7 


CLAUDE  BERNARD 

exact.  Since  then  curare  has  become  an 
instrument  in  the  hands  of  the  physiologist 
of  the  same  order  as  that  supplied  by 
anaesthetics  ;  by  enabling  him  to  abolish 
temporarily  the  movements  of  the  skeletal 
muscles  it  has  enabled  him  to  carry  out 
observations  which  could  not  have  been 
made  at  all  or  could  not  have  been  made 
satisfactorily  without  such  aid.  And  the 
knowledge  which  has  thus  been  gained  is 
indirectly  due  to  Bernard. 

In  many  of  the  instances  in  which  in  his 
writings  Bernard  has  dwelt  on  the  action 
of  curare,  he  has  in  an  almost  dramatic 
manner  insisted  upon  its  leaving  intact 
the  sensory  elements  of  the  nervous 
system.  And  indeed  there  is  every  rea- 
son to  believe  that  with  a  certain  dose  of 
the  poison  an  animal  may  be  killed  with- 
out its  sensations  being  affected  until  the 
nervous  system  is  poisoned  not  by  the  drug 

148 


OTHER    DISCOVERIES 

but  by  the  blood  ceasing  to  be  oxygenated 
owing  to  the  paralysis  of  the  respiratory 
pump.  But  Bernard  himself  came  to  recog- 
nise that  the  exact  limits  of  the  action  of  the 
poison  were  largely  determined  by  the  dose, 
that  while  a  small  quantity  in  the  blood  at 
any  one  time  affected  only  the  motor  nerves 
of  the  skeletal  muscles,  a  larger  quantity  in- 
terfered also  with  the  vaso-motor  nerves ; 
and  KoUiker  was  nearer  the  truth  than 
Bernard  when,  even  in  his  first  communi- 
cation, he  maintained  that  the  poison  could 
act  on  the  central  nervous  system  and  so 
affect  sensation  if  present  in  the  blood  in 
adequate  quantity. 

Of  hardly  less  value  than  his  work  on 
curare  was  Bernard's  analysis  of  the  physio- 
logical (poisonous)  action  of  carbonic  mon- 
oxide gas.  The  extremely  poisonous  nature, 
even  in  small  quantity,  of  this  gas,  so  apt 

149 


CLAUDE   BERNARD 

to  appear  when  combustion,  as  in  stoves, 
is  imperfect,  had  long  been  known  ;  as  had 
also  the  fact  that  though  death  through  it 
seems  to  be  a  kind  of  "  suffocation,'*  the 
blood,  during  the  poisoning  and  after  death 
is  not  as  in  ordinary  suffocation  dark, 
almost  black,  but  bright  red  in  colour, 
as  bright  or  even  brighter  than  ordinary 
arterial  blood.  But  how  the  gas  acted,  and 
how  it  caused  death,  was  unknown  until 
Bernard  took  up  the  matter.  In  respect 
to  this  also,  as  to  curare,  he  had  solved  the 
problem  some  time  before  he  formally 
announced  the  solution.  His  formal  com- 
munication to  the  Academic  des  Sciences 
was  not  made  until  September,  1858  ;i  but 
he  there  says  that  he  had  made  his  first 
observations  ten  years  before  and  had 
expounded  his  conclusions  in  his  lectures 
of    1853,    and  again    in    those   of    1856. 

I   "Compt.  Rend.,"  xlvii.  p.  393. 
150 


OTHER   DISCOVERIES 

Indeed  a  brief  account  of  these  appears  in 
Atlee's  notes  of  his  lectures,  published  in 
Philadelphia  in  1854;  and  he  himself 
included  a  somewhat  fuller  description  of  his 
results  in  his  "Lemons  sur  les  effets  des 
substances  toxiques,"  published  in  1857. 
In  any  case  he  had  solved  the  problem 
before  1857,  and  the  value  of  that 
solution  will  be  apparent  if  the  state  of 
knowledge  concerning  the  gases  of  the 
blood  be  kept  in  mind. 

Lavoisier,  in  making  known  the  fun- 
damental truth  that  the  central  fact  of 
respiration  is  the  disappearance  of  a 
certain  quantity  of  oxygen  from  the 
inspired,  and  the  appearance  of  a  certain 
quantity  of  carbonic  acid  in  the  expired 
air,  had,  at  the  beginning  of  the  century, 
propounded  the  further  view  that  the 
oxygen  goes  and  the  carbonic  comes  in 
consequence  of  a  subtle  substance  contain- 

151 


CLAUDE   BERNARD 

ing  carbon  and  oxygen  being  secreted 
from  the  blood  into  the  air  passages  and 
being  there  oxidised.  This  view,  though 
it  came  to  be  regarded  as  years  went  on 
with  increasing  doubt,  was  not  wholly 
abandoned  until  Magnus  in  1838  pub- 
lished his  researches  on  the  gases  of  the 
blood.  Those  researches  marked  an 
epoch  in  the  Theory  of  Respiration. 
Magnus  showed  that  both  arterial  and 
venous  blood  contained  both  oxygen  and 
carbonic  acid,  that  arterial  blood  con- 
tained more  oxygen  and  less  carbonic 
acid  than  did  venous,  and  that  respira- 
tion consisted  in  the  blood  gaining 
oxygen  and  losing  carbonic  acid  in  the 
lungs,  and  losing  oxygen  and  gaining 
carbonic  acid  in  the  tissues.  That  was 
a  great  step  ;  but  Magnus  maintained 
that  both  gases  were  simply  dissolved  in 
the  blood,  the    quantity  of   each    present 

152 


OTHER  DISCOVERIES 

being  determined  by  the  Jaw  of  pressures. 
This  view  held  its  position  for  many 
years.  Though  contested  by  Liebig,  it  was 
the  dominant  view  at  the  time  Bernard 
began  the  observations  with  which  we 
are  dealing.  Not  until  after  he  had 
arrived  at  the  conclusion  of  which  we 
are  about  to  speak,  namely  in  1857,  were 
Magnus's  views  overthrown  by  observa- 
tions carried  out  by  L.  Meyer  on  Magnus's 
lines,  but  leading  to  the  conclusion  that 
the  gases  of  the  blood  are  not  wholly 
present  as  merely  dissolved  gases,  but 
exist  in  some  loose  unstable  combination 
from  which  they  can,  under  appropriate 
circumstances,  be  set  free.  This  Meyer 
very  distinctly  showed  to  be  the  condition 
of  the  oxygen  in  the  blood,  but  he  failed 
to  discover  the  substance  or  substances  in 
the  blood  with  which  it  so  combined. 
The   red    corpuscles    were    suspected    to 

153 


CLAUDE   BERNARD 

be  concerned  in  the  matter  ;  but  though 
crystals,  of  what  we  now  call  hasmo- 
globin  had  been  described  by  Reichert, 
Funke  and  others,  haematin  was  still 
spoken  of  as  the  colouring  matter  of 
the  blood,  and  all  Meyer's  attempts  to 
connect  with  haematin  the  absorption 
of  oxygen  by  the  blood  failed.  Our 
knowledge  on  this  matter  was  not  put 
on  a  proper  footing  until  Hoppe  (Hoppe- 
Seyler)  in  1862  and  Stokes  in  1864 
published  their  spectroscopic  observa- 
tions. 

Meanwhile,  before  1857,  Bernard  had 
got  at  the  truth  by  help  of  carbonic 
monoxide.  He  had  certainly  made  the 
fundamental  experiments  in  1855,  and 
according  to  his  own  account  had  already 
made  some  of  them  in  1848,  having 
observed  the  pecuUar  colour  of  the  blood 
in  carbonic    monoxide  poisoning  so  early 

154 


OTHER   DISCOVERIES 

as  1842,  at  the  very  beginning  almost  of 
his  career. 

He  observed  that  blood  taken  from  the 
right  side  of  the  heart  in  animals  poisoned 
by  carbonic  oxide  and  exposed  to  an  atmo- 
sphere containing,  like  ordinary  air,  a 
known  quantity  of  oxygen,  did  not,  as  did 
normal  blood,  take  up  oxygen.  He 
further  observed  that  when  normal  blood 
was  exposed  to  an  atmosphere  of  carbonic 
monoxide  it  gave  up  oxygen  at  the  same 
time  that  it  absorbed  carbonic  monoxide, 
and  that  the  volumes  of  oxygen  so  given 
up  and  carbonic  monoxide  so  absorbed 
were  equal.  Reflecting  that  the  different 
colours  of  arterial  and  venous  blood  must 
be  due  to  the  behaviour  of  the  red 
corpuscles  in  relation  to  the  gases  of  the 
two  kinds  of  blood,  he  jumped,  as  it  were, 
to  the  conclusion  that  the  red  corpuscles 
were  concerned  in  the  retention  both  of 

155 


CLAUDE   BERNARD 

oxygen  and  carbonic  oxide  by  the  blood. 
This  was  confirmed  by  the  further  obser- 
vation that  the  beneficial  effects  of  the 
transfusion  of  blood,  which  are  obviously 
due  to  the  red  corpuscles,  since  serum 
free  from  corpuscles  has  no  such  effects, 
were  absent  when  the  blood  used  was 
carbonic  monoxide  blood.  This  gave  him 
the  key  to  an  understanding  of  the  way 
in  which  carbonic  monoxide  poisons  the 
animal  body.  "  I  was  thus  led,"  says  he, 
*'  to  find  that  this  gas  rapidly  poisons 
animals,  because  it  instantly  displaces  the 
oxygen  of  the  red  corpuscles  and  cannot 
itself  be  subsequently  displaced  by 
oxygen."  "  The  animal  dies  because  the 
red  corpuscles  are,  as  it  were,  paralysed 
and  circulate  as  inert  bodies  devoid  of  the 
power  of  sustaining  life." 

Some  of  the  details  of  the  experiments 
on  which  Bernard  based  this  view  may  be 

156 


OTHER   DISCOVERIES 

open  to  criticism,  but  it  remains  never- 
theless true  that  by  these  researches  he 
secured  a  threefold  gain.  He  explained 
the  mode  of  action  of  carbonic  oxide,  and 
so  opened  the  way  for  rational  remedial 
measures.  He  introduced  an  easy  and 
ready  method  of  measuring  the  quantity 
of  available  respiratory  oxygen  in  any 
given  quantity  of  blood,  a  method  which, 
both  in  his  own  hands  and  in  those  of 
others,  has  proved  of  great  service.  And, 
by  a  sort  of  inspiration,  he  anticipated  the 
conclusions  arrived  at  in  a  more  laborious 
way  by  his  German  brethren,  and  reached, 
almost  in  one  step,  a  correct  view  of  the 
nature  of  the  respiratory  process.  This 
view,  moreover,  assisted  by  the  method, 
enabled  him  to  push  forward  his  inquiries 
into  the  functions  and  behaviour  of  the 
blood  as  the  great  "  internal  medium " 
on  which  the  tissues   live,  and  thus  inci- 

157 


CLAUDE  BERNARD 

dentally  led  him,  as  we  have  seen,  to  the 
discovery  of  the  distinction  between  vaso- 
constrictor and  vaso-motor  nerves. 

There  are  many  other  results  which 
Bernard  arrived  at,  such  as  the  so-called 
paralytic  secretion,  the  supposed  reflex 
activity  of  the  sympathetic  ganglia,  and 
others  ;  but  on  these  we  need  not  dwell  in 
detail,  though  they  are  often  quoted  in 
physiological  literature. 

One  observation  of  his,  however,  perhaps 
deserves  notice.  In  the  "  fifties "  biolo- 
gists, especially  perhaps  in  France,  were 
engaged  in  a  fierce  controversy  about 
spontaneous  generation,  a  controversy  laid 
to  rest  in  the  main  by  Pasteur,  and  now 
well  nigh  forgotten.  To  that  controversy 
Bernard  made  a  notable  contribution  in 
1 858.1  He  showed  that  the  growths 
which    readily  appear    in   a    solution  con- 

I  "Ann.  d.  Sc.  Nat.,"  ix.,  1858,  p.  360. 
158 


OTHER  DISCOVERIES 

taining  gelatine  and  dextrose  exposed  to 
the  air,  do  not  appear  if  the  solution  be 
supplied  exclusively  with  air  which  has 
passed  through  a  red-hot  tube.  He 
argued  that  the  growths  which  usually 
appear  are  not  spontaneous  in  origin  but 
have  their  source  in  air-borne  germs,  and 
the  red-hot  tubes  killed  the  germs  on  their 
v/ay  to  the  solution.  Much  of  Pasteur's 
refutation  oi  the  spontaneous  generation 
theory  was  on  the  lines  of  Bernard's 
experiment. 


159 


VII 

His  Later  Writings 

FROM  the  preceding  chapters  it  will  be 
seen  that  all,  or  nearly  all,  Bernard's 
great  achievements  were  accomplished 
during  that  period  of  his  life  which  ended 
with  the  year  i860.  Looking  more 
closely  we  may  see  that  the  essential  results 
of  his  two  greatest  discoveries,  the  glyco- 
genic function  of  the  liver  and  the  vaso- 
motor system,  were  gained  so  early  as 
about  1850,  within  the  first  ten  years  of 
his  career  as  an  investigator. 

The  great  truths,  which  it  was  given  to 
him  to  lay  bare,  were  not  reached  by  the 
help    of    easy    circumstances    and    ample 

160 


HIS   LATER   WRITINGS 

opportunities  for  inquiry  such  as  fall  to  the 
lot  of  at  least  most  of  the  young  men  of 
science  of  to-day.  I  am  not  speaking  of 
the  attendant  difficulties  of  earning  the  daily 
bread ;  these  are  known,  perhaps  one  may 
say  happily  known,  to  almost  all  young 
inquirers  of  all  times.  I  am  contrasting 
Bernard's  surroundings  at  the  commence- 
ment of  his  career  with  those  of  the  young 
man  who  at  the  present  time  desires  to 
devote  himself  to  scientific  research.  The 
latter,  at  least  in  most  cases,  finds  in  some 
way  or  other  access  to  a  well-furnished 
laboratory,  in  which  the  path  of  investiga- 
tion is  made  smooth,  perhaps  in  some  cases 
too  smooth,  for  him,  in  which  adequate 
apparatus  is  placed  at  his  disposal,  and  in 
which  he  is  at  once  trained  in  the  technique 
of  inquiry  and  guided  in  his  thoughts  by 
the  sympathetic  and  suggestive  words  of 
a  wise  and  experienced  master. 

i6i  M 


CLAUDE   BERNARD^ 

None  of  these  things  came  to  Bernard. 
He  had,  it  is  true,  encouragement  and  an 
example  in  Magendie,  but  hardly  more  ; 
and  even  this  was  not  much.     So   far  as 
example  went,  beyond  a  strenuous  desire 
to  put  everything  to  the   test  of  experi- 
ment, there  was  little  of  intellectual  train- 
ing   which    Magendie    could    impart    to 
Bernard.     Indeed,  it  could  not  have  been 
long  before  the  pupil  began  to  feel,  as  the 
stronger    man    of    the    two,    his    natural 
enthusiasm  for  his  master  checked    by  a 
growing  conviction  that  the  master's  hand 
was  often  pointing  the  wrong  way.     Nor 
in    the    details  of  experimental  execution 
was    there    much    for    Bernard    to   learn  ; 
indeed,  it  was  for  the  most  part  the  other 
way.     After  the  third  or  fourth  lecture, 
at  which  Bernard  assisted  as  freparateur^ 
Magendie,    struck   with    the    superb  skill 
with   which    Bernard   had   conducted   the 

162 


HIS   LATER   WRITINGS 

lecture  demonstrations,  said,  in  his  usual 
gruff  way,  as  he  left  the  lecture-room  at 
the  close  of  the  lecture,  "  You  are  a  better 
man  than  I  am." 

In  the  way  of  material   advantages  for 
research  Magendie  had  little  to  offer  to  his 
assistant.     As  Bernard   himself  (''  Physio- 
logie  generale,"   p.  203)  has  told  us,  ex- 
perimental   physiology    was    then    looked 
down  upon.     Natural  history  was  in  the 
ascendant.     Botany,  zoology,  and  geology 
had  their  museums.     The  great  and  domi- 
nant  Cuvier   mocked    at    experiments   on 
living     animals,      maintaining     that    they 
were  simply  sources    of  erroneous  views. 
Chemistry  was  rising  fast  and  was  being 
provided  with  adequate  laboratories.     But 
for  physiology  nothing  was    being   done. 
On  the  contrary,  it  was  being  persecuted 
and  reviled.     "  In  those  days  the  physio- 
logist had   need  of  a  real  passion  for  his 

163 


CLAUDE   BERNARD 

science,  and  in  order  to  ward  off  fatal  dis- 
couragement had  to  possess  his  soul  of 
high  courage  and  great  patience.  So  soon 
as  an  experimental  physiologist  was  dis- 
covered he  was  denounced  ;  he  was  given 
over  to  the  reproaches  of  his  neighbours 
and  subjected  to  annoyances  by  the 
police." 

In  the  College  de  France,  devoted 
though  it  was  to  scientific  inquiry,  no 
better  place  as  a  laboratory  was  found  for 
Magendie  than  a  corner,  spoken  of  as  "a 
damp  and  dark  lair,"  a  hiding-place  for  a 
wild  beast.  And  Bernard  himself  has  said  : 
"  I  had  ample  opportunity,  while  I  served 
as  his  assistant,  to  note  the  continual 
obstacles  which  the  administration  of  the 
college  put  in  his  way." 

It  was  not  in  Magendie's  power  to  offer 
his  assistant  opportunities  for  research,  and 
Bernard,  even  after  his  appointment  to  the 

164 


HIS   LATER   WRITINGS 

assistantship,  had  to  carry  on  his  experi- 
mental inquiries  in  some  temporary 
laboratory  of  his  own,  or  in  that  of  one 
of  his  chemical  friends,  such  as  in  that  of 
Pelouze.  We  have  already  (p.  12)  said 
something  of  the  circumstances  amid  which 
he  made  his  first  researches  ;  and  the 
following  story  which  he  tells  in  his 
*'  Physiologie  generale,"  illustrates  the 
nomadic  character  of  his  experimental 
installations,  and  the  difficulties  amid 
which  he  prosecuted  his  early  inquiries. 

"About  1844  I  was  studying  the 
digestive  powers  of  gastric  juice  by  the 
help  of  the  method  introduced  by  Blond- 
lot,  namely,  that  of  collecting  gastric  juice 
by  means  of  a  cannula,  or  sort  of  silver  tap, 
fitted  into  the  stomach  of  a  live  dog  in 
such  a  way  that  the  health  of  the  animal 
does  not  in  the  least  suffer  thereby.  Just 
then   the    celebrated    surgeon    of   Berlin, 

165 


CLAUDE  BERNARD 

DiefFenbach,  was  on  a  visit  to  Paris  ;  and, 
hearing  of  my  experiments  through  my 
friend  Pelouze,  he  was  anxious  to  witness 
the  operation  of  the  introduction  of  the 
gastric  cannula.  Informed  of  his  wish,  I 
hastened  to  gratify  it,  and  performed  the 
experiment  on  a  dog  in  the  chemical 
laboratory  which  Pelouze  then  had  in  the 
Rue  Dauphine.  After  the  operation  the 
animal  was  shut  up  in  the  yard  of  the 
laboratory  in  order  that  we  might  ex- 
amine it  again  later  on.  But  on  the 
morrow  it  was  found  that  the  dog  had, 
in  spite  of  precautions,  escaped,  carrying 
still  in  its  belly  the  accusing  cannula  of 
a  physiologist.  Some  days  afterwards, 
quite  early  in  the  morning,  before  I  had 
got  up,  I  was  visited  by  a  person  who 
came  to  tell  me  that  the  police  commis- 
sioner  of  the  quarter  of  the  Ecole-de- 
Medecine  wanted  to  speak  with  me,  and 

i66 


HIS   LATER   WRITINGS 

requested    me    to    call    on    him.      In    the 
course  of  the  day  I  presented  myself  at  the 
police  office  in   the   Rue  du  Jardinet.     I 
found    there  a  little    old    man  of  a  very 
respectable  appearance,  who    received    me 
very    coldly,    and    at    first    said    nothing. 
Then,  taking  me  into  an  adjoining  room, 
he  showed  me,  to  my  great  astonishment, 
the    dog    on   which   I    had    operated   in 
Pelouze's  laboratory,   and   asked  me  if  I 
admitted   having    placed   in   the    dog  the 
instrument  which  he  had  in  his  belly.     I 
replied    in  the   affirmative,   adding  that  I 
was   delighted  to   find  my  cannula  again, 
for  I  had  given  it  up  as  lost.     My  answer, 
however,    instead    of  satisfying    the    com- 
missioner, appeared  to  anger  him,  for  he 
addressed  to  me  an  admonition  couched  in 
the  severest  terms,  accompanied  by  threats 
at  my  audacity  in  having  taken  his  dog  to 
experiment  on.     I    explained  that  it  was 

167 


CLAUDE   BERNARD 

not  I  who  had  taken  his  dog,  but  that  I 
had  bought  it  of  the  men  who  were  in  the 
habit  of  selling  dogs  to  the  physiologists, 
and  who  stated  that  they  were  employed 
by  the  police  to  collect  stray  dogs.  I 
added  that  I  regretted  having  been  the 
involuntary  cause  of  the  pain  which  the 
misfortune  of  his  dog  had  caused  him, 
that  the  animal  would  not  die  of  it,  and 
that  there  v/as  only  one  thing  to  do, 
namely,  to  let  me  take  back  my  silver 
cannula  and  for  him  to  keep  the  dog. 
These  last  words  at  once  made  the  com- 
missioner change  his  manner  of  speaking, 
and  completely  appeased  his  wife  and 
daughter.  I  removed  my  instrument, 
and  on  leaving  promised  to  call  again. 
And,  indeed,  I  visited  the  Rue  du  Jardinet 
several  times.  In  a  few  days  the  dog  was 
completely  cured,  I  became  a  friend  of 
the  commissioner,  and  could  henceforward 

i68 


HIS   LATER   WRITINGS 

count  on  his  protection.  Indeed  this  led 
me  to  establish  my  laboratory  within  his 
district  ;  and  for  some  years,  until,  in  fact, 
I  was  appointed  deputy  to  Magendie  at 
the  College  de  France,  I  was  enabled  to 
continue  my  private  courses  of  experi- 
mental physiology  under  the  licence  and 
protection  of  the  commissioner,  whereby 
I  was  saved  many  disagreeable  incidents." 

In  1847  Magendie's  increasing  infirmi- 
ties led  to  Bernard's  being  appointed  his 
Deputy  at  the  College  de  France,  and  a 
career  now  seemed  to  be  secured  to  him. 
He  could  henceforward  work  in  an  official 
laboratory  ;  and  it  was,  as  we  have  seen, 
during  the  succeeding  few  years  that  his 
most  brilliant  work  was  done. 

Yet  in  1851,  at  the  very  time  that  he 
was  unlocking  the  gates  of  Fam.e,  conscious 
though  he  must  have  been  of  the  high 
value   of  the  truths  which  he  was  begin- 

169 


CLAUDE   BERNARD 

ning  to  make  known,  he  was  despairing 
of  the  future.  The  path  of  the  experi- 
mental physiologist  seemed  so  doubtful, 
the  difficulties  so  many  and  so  pressing, 
the  hopes  of  success  so  few  and  so 
shadowy,  that  he  at  this  time  had  serious 
thoughts  of  abandoning  a  career  of  science, 
and  of  devoting  himself  to  active  practice 
as  a  surgeon.  His  domestic  relations 
probably  had  much  to  do  with  his  dis- 
couragement ;  for  he  had,  unhappily, 
married  a  wife  who  was  in  no  way  a 
helpmeet  to  him.  Hers  was  a  nature 
too  commonplace  to  rise  to  any  sympathy 
with  his  intellectual  aspirations  ;  she  was 
not  prepared,  as  he  was,  to  live  laborious 
days  on  narrow  means,  in  order  that  the 
world  might  be  the  richer  for  the  truths 
which  he  by  patient  toil  might  reap.  She 
desired  that  the  ability,  which  she  learned 
from  those  around  her  gave   promise  of 

170 


HIS   LATER   WRITINGS 

being  of  the  kind  which  men  call  genius, 
should  find  immediate  reward  in  that 
"  which  all  women  admire,"  and  should 
change  hardships  and  self-denials  into  ease 
and  affluence.  She  thought  that  the  life 
of  a  successful  practitioner,  riding  to-day 
in  his  carriage  and  to-morrow  forgotten, 
was  far  more  to  be  desired  than  the  life 
of  a  student  whose  present  lay  in  obscurity, 
and  whose  future  could  not  be  foretold. 

Happily  Bernard  had  in  him  that  which 
armed  him  against  the  temptation  to  leave 
the  plough  to  which  he  had  put  his  hand. 
When  in  1847  he  gave  his  first  lecture  as 
deputy  for  Magendie,  he  began  with  these 
words  :  "  Scientific  medicine,  gentlemen, 
which  it  ought  to  be  my  duty  to  teach 
here,  does  not  exist."  He  said  this  know- 
ing that  he  who  was  speaking  had  both 
the  ideas  and  the  skill  to  realise  those 
ideas,  such  as  would  go  far  to  create  the 

171 


CLAUDE   BERNARD 

lacking  science.  With  this  consciousness 
of  his  power  he  could  not  but  go  on. 
Nor  had  he  long  to  wait  before  assurance 
came  to  him  that  he  was  not  mistaken  as 
to  the  path  which  he  had  marked  out  for 
himself.  Whispers  ran  round  among  the 
Olympians  of  science  that  a  young  physio- 
logist was  doing  remarkable  work,  whispers 
which  soon  strengthened  into  loud  voices 
of  unstinted  praise.  And  speech  was 
before  long  followed  by  action.  Magendie 
still  lingering  on,  Bernard's  position  at 
the  College  de  France  was  the  insecure 
and  insufficient  one  of  a  mere  deputy, 
whose  term  of  office  was  dependent  on  the 
life  of  another.  Recognising  this,  and 
recognising  also  that  the  physiology  which 
Bernard  was  advancing  and  expounding, 
was  not  a  mere  technical  adjunct  to  the 
art  of  medicine,  but  was  of  the  kind  which 
claimed  to  be  considered   as   a  branch  of 

172 


HIS   LATER   WRITING 

knowledge,  of  value  for  its  own  sake  as 
a  constituent  part  of  philosophy,  the 
authorities  created  in  the  faculty  of  Science 
of  the  University  of  Paris,  at  the  Sorbonne, 
a  new  chair  of  General  Physiology,  and 
placed  him  in  it  as  the  first  occupant. 
Though  the  post  carried  with  it  neither 
laboratory  nor  assistants,  it  at  least  gave 
Bernard  an  honourable  position.  Further 
recognition  came  in  the  same  year  in  the 
form  of  election  into  the  Academy  of 
Medicine  and  Surgery,  in  succession  to  the 
great  surgeon  Roux.  And  in  1855,  upon 
the  death  of  Magendie,  Bernard  was  without 
hesitation  called  to  the  vacant  chair  and 
made  full  Professor  at  the  College  de 
France.  Henceforward  there  could  be  no 
question  of  his  turning  back  from  science. 
During  the  next  few  years  his  activity 
was  enormous.  He  extended  and  com- 
pleted  his   great   discoveries,   and   within 

173 


CLAUDE   BERNARD 

seventeen  years  from  the  beginning  of  his 
career  as  an  inquirer,  while  he  was  as  yet 
some  three  years  short  of  fifty  years    of 
age,   he    had    brought    to   the   science  for 
the  sake  of  which  he  had  deserted  litera- 
ture, all  the  wealth  of  riches  on  which  we 
have  dwelt  in  preceding  chapters.     At  the 
same  time  he  was  delivering  lectures  both 
at  the  College  de  France  and  at  the  Sor- 
bonne,  a  course  of  forty  lectures  a  year 
in  each   place.      These   lectures   were  no 
deliverances    of    academic    platitudes,    no 
formal  expositions  of  acknowledged  doc- 
trines,  composed   once   for    all,   and   that 
without  great    labour,  and  repeated  with 
but  little  change  year  after  year.     At  the 
College  de  France,  as  we  have  seen,  his 
hand  was  free  ;  he  could  lecture  on  what 
he  liked  and  how  he  liked.     At  the  Sor- 
bonne,  the  regulations  for  the  chair  pre- 
scribed lectures  of  a  more  didactic  kind  ; 

174 


HIS   LATER   WRITINGS 

but  Bernard,  ignoring  the  regulations, 
lectured  there  also  in  the  way  which  he 
thought  best,  and  no  one  gainsayed  him. 
In  both  places  he  chose  some  subject  for  a 
course,  and  treated  it  as  an  inquiry,  to  be 
developed  as  the  course  went  on  by  the 
help,  not  only  of  old,  but  also  of  new 
experiments.  Each  course  which  he  gave 
was  as  a  mere  course  a  burden  to  him  ;  he 
took  no  pleasure  in  exposition,  this  indeed 
was  only  weariness  to  him  ;  it  was  inquiry, 
and  inquiry  alone,  which  satisfied  his  soul. 
In  fact,  he  largely  used  his  lectures  as  a 
means  of  making  known  new  results  and 
new  or  corrected  and  extended  views.  In 
many  instances  the  communication  in  which 
he  made  known  some  new  result  to  the 
Academie  des  Sciences  or  to  the  Societe  de 
Biologic,  seems  all  too  brief  and  imperfect, 
in  fact,  sometimes  almost  bald.  One  has  to 
look  to  the  published  Lemons,  in  which  the 

175 


CLAUDE    BERNARD 

matter  is  more  fully  treated  of,  in  order 
to  get  the  author^s  fuller  exposition  and 
to  learn  his  more  mature  view.  Many  of 
Bernard's  results,  indeed,  can  only  be 
found  in  these  Lemons,  and  it  is  to  these 
that  we  have  to  look  for  an  adequate 
exposition  of  many  of  his  ideas.  Con- 
scientiously reported  by  one  or  other  of 
his  talented  pupils,  and  carefully  revised 
by  his  own  hand,  the  series  of  lectures 
thus  delivered  and  published  constitute 
Bernard's  great  contribution  to  physio- 
logical literature. 

In  these  he  developed  more  fully  his 
views  on  the  questions  involved  in  his  own 
researches,  and  his  conceptions  of  general 
physiological  truths.  Taken  together  they 
constitute  his  testament  in  which  may  be 
found  at  once  an  account  of  his  own 
labours,  an  exposition  of  the  aims  and 
methods  of  physiology,  and  a  vindication 

176 


HIS   LATER   WRITINGS 

of  the   value  of  the  science   to   which  he 
devoted  his  hfe. 

The  series  begins  with  the    "  Lemons  de 
Physiologie      experimentale,"      the     first 
volume    of    which,    published    in     1855, 
contains     the     course     delivered     at     the 
College    de    France     in     the    winter     of 
^^54-55>  and  deals  chiefly  with  the  phy- 
siology of  sugar  and  with  the  glycogenic 
function    of  the    liver,    while    the   second 
volume  which  was  published  in  the  next 
year  is  devoted  to  digestion,  and  includes 
an  account  of  the  new  results  about  the 
pancreas. 

Next  followed,  in  1857,  the  "Lemons  sur 
les  effets  des  substances  toxiques  et 
medicamenteuses,"  delivered  in  1856,  also 
at  the  College  de  France,  in  which  he,  as  we 
have  seen,  expounded  his  views  on  the 
action  of  curare  and  carbonic  monoxide, 
though  dwelling  also  on  strychnine,  nicotine, 

^11  N 


CLAUDE   BERNARD 

ether,  and  other  chemical  substances. 
The  dominant  idea  of  the  book  is  to 
develope  the  value  of  a  drug  as  a  means 
of  physiological  analysis. 

In  the  next  year,  1858,  he  published  his 
*'  Lemons  sur  la  physiologie  et  la  pathologic 
du  systeme  nerveux,"  delivered  at  the 
College  de  France  in  the  winter  of  1856-57. 
The  first  volume  is  of  the  nature  of  a 
general  exposition,  though  three  lectures 
are  devoted  to  the  diabetic  puncture  ;  the 
second  deals  with  the  physiology  of  the 
several  cranial  nerves,  with  which,  as  the 
pupil  of  Magendie,  Bernard  was  thoroughly 
conversant,  and  on  which  he  himself  had 
worked  ;  and  the  last  two  lectures  con- 
stitute an  exposition  of  the  new  views 
as  to  the  sympathetic  nerve. 

In  1859,  appeared  in  two  volumes  the 
"  Lemons  sur  les  proprietes  physiologiques 
et  les  alterations  pathologiques  des  liquides 

178 


HIS   LATER   WRITINGS 

de  Torganisme,"  in  which  developing  his 
pregnant  idea  of  the  blood  as  the  ''  internal 
medium "  on  which  the  tissues  live,  he 
discoursed  of  the  physiology  of  that  and 
other  fluids  of  the  body  in  health  and  in 
disease.  These  seven  volumes  of  lectures, 
all  delivered  at  the  College  de  France,  he 
some  years  later  formally  presented  to  the 
Academy  of  Sciences. 

They  were  followed  in  turn  by  the 
"  Lemons  de  pathologie  experimentale," 
"  Lemons  sur  les  anesthetiques  et  sur 
I'asphyxie,"  "  Lemons  sur  la  chaleur 
animale,"  "  Legons  sur  le  diabete," 
*' Lemons  sur  les  phenomenes  de  la  vie," 
and  lastly  by  the  "  Legons  de  Physiologie 
operatoire."  They  form  altogether  17 
octavo  volumes.  He  who  reads  the  whole 
series  consecutively  will  naturally  come 
upon  much  repetition,  especially  in  the 
exposition  of  ideas  ;    but  that  is  insepar- 

179 


CLAUDE  BERNARD 

able  from  the  circumstances  of  the  delivery 
of  the  lectures  and  of  their  publication. 
The  more  important  of  the  topics  dwelt 
upon  in  these  several  courses  of  lectures 
have  been  referred  to  in  their  proper  place 
in  the  preceding  chapters.  It  may,  how- 
ever, be  worth  while  to  point  out  the 
especial  value  of  the  lectures  on  animal 
heat,  not  only  in  that  they  contain,  as  we 
have  already  indicated,  an  exposition  of 
Bernard's  views  as  to  influences  of 
nerves  on  the  chemical  changes  of  the 
tissues  and  so  on  the  development  of  heat, 
but  also  and  perhaps  especially  in  that 
they  embody  the  results  of  his  observa- 
tions on  the  topography  of  bodily  tempera- 
ture, on  the  differences  of  temperature 
presented  by  different  organs  and  parts, 
and  on  the  causes  of  those  differences.  For 
Bernard  largely  extended,  or  perhaps  rather 
established,  our  knowledge  of  this  subject. 

i8o 


HIS   LATER   WRITINGS 

In  the  long  bibliographical  list  of 
Bernard's  writings,  a  break  is  found  in 
the  year  1863.  While  from  1843  onward, 
each  year  is  marked  by  some  and  generally 
by  many  utterances,  he  published  nothing 
between  the  fall  of  1862  and  the  spring  of 
1864  ;  in  1863  he  was  wholly  silent. 
The  incessant  labours  of  the  preceding 
years  had  told  upon  him  ;  and  in  the 
winter  of  1862-63  he  wholly  broke  down. 
The  state  of  his  health  gave  great  anxiety 
to  his  friends,  they  feared  that  the  brilliant 
inquirer  was  prematurely  to  be  taken  away 
from  them.  The  exact  nature  of  the 
malady  which  attacked  him  was  in  many 
ways  obscure.  It  was  an  abdominal 
affection,  apparently  an  abscess,  giving 
rise  to  periodical  attacks  of  fever  and 
acute  pain,  with  intervening  remissions. 
An  exact  diagnosis  was  never  made,  but 
it    seems    not    unlikely   that    the    illness 

181 


CLAUDE   BERNARD 

would  nowadays  have  been  recognised 
as  appendicitis.  He  suffered  from  it  at 
intervals  until  1866-67,  when,  ^.fter  a  most 
severe  attack,  accompanied  by  intense  fever, 
during  which  his  life  was  despaired  of,  the 
abscess  appears  to  have  discharged  into  the 
bowel.  He  then  slowly  recovered  his 
health,  and  by  1869-70  had  become  once 
more  sound  and  strong. 

The  early  attacks  of  the  malady  led 
him  in  1 862-63  to  desert  his  laboratory  and 
seek  for  restoration  to  health  by  a  long 
sojourn  in  his  ancestral  home  at  St.  Julien. 
The  rural  abode  with  its  surrounding 
vineyards  had  not  passed  into  other  hands. 
Bernard,  since  the  death  of  his  parents,  had 
kept  possession  of  it,  and  thither  he  had 
been  wont  to  return  each  autumn,  restoring 
his  mind  and  body  during  his  vacations 
with  the  pure  air  of  the  country  and  the 
quiet  occupations    of    a   rural  proprietor. 

182 


HIS    LATER   WRITINGS 

Here,  in  the  soothing  autumn  days,  he 
went  to  and  fro,  tending  his  garden, 
caring  for  his  fruit  trees,  many  of  which 
had  been  grafted  by  his  own  hands,  and 
above  all  watching  over  the  vintage,  the 
produce  of  which  appeared  upon  his  table 
at  Paris. 

In  this  quiet  retreat  he  spent  the 
greater  part  of  the  year  1863  ;  but  as 
health  and  vigour  came  back,  at  least 
in  part,  to  him,  the  daily  round  of 
rural  pleasures  and  occupations  soon 
began  to  be  too  small  to  fill  his  mind. 
Away  from  his  laboratory  and  instruments, 
experimental  inquiry  was  impossible  for 
him  ;  but  the  science  of  his  adoption  was 
ever  present  to  his  mind,  and  he  made 
use  of  this  enforced  leisure  and  his 
returning  vigour  to  develope  in  a 
systematic  manner  those  views  on  the 
nature  of  the  true  methods  of  physiological 

183 


CLAUDE   BERNARD 

inquiry,  which  from  the  very  first  had 
guided  him  in  his  investigations,  and  of 
which  he  had  from  time  to  time,  as  occasion 
presented, given  out  fragmentary  utterances. 
The  result  was  a  volume,  published  in  1865, 
entitled  '*  Introduction  to  the  Study  of 
Experimental  Medicine,"  and  intended  to 
serve  as  the  introduction  to  a  larger  work 
with  the  title  "  Principles  of  Experimental 
Medicine  ;"  this  latter  however  never  saw 
the  light. 

In  this  "  Introduction  "  Bernard  ex- 
pounded that  conception  of  biological 
inquiry  to  which  he  gave  the  name  of 
"  determinism."  When  he  began  his 
medical  studies  he  found,  as  we  have 
already  said,  the  opinion  very  common — 
his  teacher  Magendie  himself  holding  it — 
that  really  vital  phenomena  were  not  sub- 
ject to  law,  and  therefore  were  beyond  the 
pale  of  scientific  investigation  by  experiment 

184 


HIS    LATER   WRITINGS 

and  observation,  this  being  applicable  only 
to  the  "  physical  phenomena  of  life."  Ber- 
nard's position  was  that  the  manifestations 
of  the  properties  of  living  bodies  are  bound 
up  with  the  existence  of  certain  physico- 
chemical  phenomena,  and  that  the  latter 
furnish  the  conditions  of  the  former.  He 
insisted  that  in  living,  no  less  than  in  non- 
living bodies,  natural  phenomena  are  rigor- 
ously dependent  on  conditions,  and  that  in 
the  case  of  both  the  object  of  scientific 
inquiry  is  to  lay  bare  the  connection  of  the 
phenomena  with  the  conditions.  He  ex- 
pressed himself  somewhat  as  follows  : 
'*  In  both  biological  and  chemico-physical 
studies  the  inquirer  meets  with  a  double 
set  of  conditions.  He  has  to  consider,  on 
the  one  hand,  the  body  in  which  the  pheno- 
mena occur,  and,  on  the  other  hand,  the 
external  circumstances,  or  the  '  medium  ' 
by  which  the  manifestations  of  the  pheno- 

185 


CLAUDE   BERNARD 

mena  are  determined  or  provoked.  In 
both  studies  the  rigorous  determination  of 
the  conditions  is  possible  because  matter 
itself  is  devoid  of  spontaneity,  in  both 
studies  the  limits  of  our  knowledge  are 
the  same,  in  both  studies  in  order  to  arrive 
at  the  '  determinism  '  of  the  phenomena,  it 
is  necessary  to  bring  those  phenomena  into 
experimental  conditions  as  definite  and  as 
simple  as  possible.  The  experimental 
physiologist  knows  nothing  either  of 
spiritualism  or  of  materialism  ;  such  words 
belong  to  an  effete  philosophy.  We  do  not 
know  and  never  shall  know  either  spirit  or 
matter.  First  causes  do  not  belong  to  the 
domain  of  science  ;  they  will  ever  be  beyond 
our  grasp,  whether  we  are  dealing  with 
living  or  with  non-living  things.  The  true 
experimental  method  has  no  part  what- 
ever in  the  chimerical  search  of  the  '  vital 
principle  ; '  there  is  no  more  a  vital  force 

i86 


HIS   LATER   WRITINGS 

than  there  is  a  mineral  force,  or,  if  one 
prefers  to  say  so,  the  one  exists  quite  as 
much  as  the  other." 

To  push  forward  a  vigorous  and  exact 
analysis  by  physical  and  chemical  means  of 
the  phenomena  of  living  bodies,  was  Ber- 
nard's conception  of  the  task  of  the  physio- 
logist, the  analysis  being  carried  out  either 
by  simple  observation  or  that  ''  provoked 
observation "  which  is  called  an  experiment. 
This  led  him,  in  the  work  in  question,  to 
caustic  remarks  on  systems  and  doctrines. 
"  Experimental  medicine,  that  is  physio- 
logy, belongs  to  no  medical  doctrine  and 
to  no  philosophic  system." 

It  is  worthy  of  note  that  in  his  various 
writings  Bernard  repeatedly  uses  the  phrase 
"  experimental  medicine  "  as  identical  with 
"  physiology."  To  his  mind  it  was  per- 
fectly clear  that  the  treatment  of  disease 
was   simply    the    practical    application    of 

187 


CLAUDE  BERNARD 

pathological  truths  ;  and  it  was  equally 
clear  that  all  distinctions  between  patho- 
logy and  physiology,  as  those  between 
health  and  disease,  were  artificial,  or  of  the 
surface  only.  To  him  the  phenomena  of 
the  living  body  presented  the  same  funda- 
mental features,  and  had  to  be  studied  by 
the  same  canons  of  inquiry,  whether  the 
body  in  which  they  appeared  were  called 
sick  or  called  sound.  But,  though  he  never 
doubted  in  the  progressive  power  to  solve 
the  problems  of  disease  of  a  growing 
physiology,  which  increasingly  laid  hold 
of  the  deeper  and  more  general  laws  of 
life,  he  saw  the  dangers  which  beset  the 
premature  application  to  practical  needs  of 
unripe  and  superficial  physiological  views. 
He  says  at  p.  348  of  the  work  of  which  we 
are  speaking — 

"  But    no   one  in  the  present    state  of 
biological  science  can  pretend  that  physiology 

188 


HIS    LATER   WRITINGS 

is  able  to  supply  complete  solutions  of  patho- 
logical problems ;  we  must  ever  strive  to  solve 
those  problems  by  physiological  inquiries, 
for  that  is  the  true  scientific  path  ;  but  we 
must   carefully  guard   against  the   illusion 
that  we  have  already  gained  the  solution. 
Hence,  the  prudent  and  reasonable  course 
at  the  present  moment  is  to  explain  all  that 
part  of   disease    which    can    be    explained 
by  physiology,  and  to  leave  that  which  we 
cannot  so  explain  to   be  explained  by  the 
future  progress  of  biologic  science.     This 
kind   of  successive   analysis,  which,  in   its 
application   to  pathological    phenomena  is 
carried    only    so    far    as    the    progress  of 
physiological  science  permits,  isolates  little 
by  little,  by  way  of  elimination  as  it  were, 
the  essential  element  of  the  disease  which 
is    thus    being    studied,    lays    hold    of  its 
characters    with    greater    exactitude,    and 
allows  therapeutic  efforts    to  be   directed 

189 


CLAUDE   BERNARD 

with  greater  certainty.  Besides,  with 
progressive  analytic  advance,  the  proper 
character  and  physiognomy  of  the  disease 
are  preserved.  But  if,  instead  of  this,  some 
delusive  approach  of  physiology  and  patho- 
logy gives  rise  to  the  ambition  to  explain 
prematurely  at  one  step  the  whole  of  the 
disease,  then  one  loses  sight  of  the  patient, 
one  gets  a  wrong  idea  of  the  disease,  and 
by  a  false  application  of  physiology,  experi- 
mental medicine  is  hindered  instead  of 
being  assisted  in  its  progress." 

No  less  clear  than  his  views  of  the  rela- 
tion of  physiology  to  medicine  were  his 
conceptions  of  the  philosophical  aspects  of 
physiology.  In  many  popular  writings 
may  often  be  found  the  idea  that  the  pro- 
gress of  the  experimental  sciences,  such  as 
physiology,  is  the  result  of  a  combination 
of  the  labours  of  two  kinds  of  men.  In 
such   writings  it  is  taught   that   the   new 

190 


HIS   LATER   WRITINGS 

facts  of  science  are  gathered  in  by  a  labo- 
rious set  of  men  who  make  experiments 
and  observations,  and  thus  bring  to  light 
new  things  ;  but  who,  humble  in  nature, 
and  lacking  the  power  of  insight  into  deep 
truths,  leave  the  truths  thus  discovered  to 
be  dealt  with  by  higher  minds,  who,  re- 
lieved from  the  tedious  labour  of  collecting 
facts,  can  spend  all  their  energy  in  the 
elaboration  of  great  generalisations.  The 
former  are,  in  the  eyes  of  the  popular 
writers  of  whom  we  are  speaking,  men 
of  science  in  the  general  acceptation  of  that 
term ;  such  men  are  happily  abundant. 
The  latter,  much  more  rare  in  their  occur- 
rence, are  spoken  of  as  philosophers.  The 
former  are  mere  labourers,  delving  after 
little  truths ;  the  latter  hold  the  lamp 
which  lights  the  others  to  their  work. 
The  writers  in  question  point  to  Francis 
Bacon  as  such  a  philosopher,  such  a  holder 

191 


CLAUDE   BERNARD 

of  the  lamp,  and  seem  to  think  that  to  the 
light  shed  by  him,  the  great  advancement 
of  natural  knowledge  which  marked  his 
time,  and  the  times  which  followed,  was 
mainly  due. 

Such  was  not  Bernard's  view.  He  says, 
*'  men  of  science,  as  Maistre  has  said,  make 
their  discoveries,  work  out  their  theories, 
and  build  up  their  science,  without  the 
aid  of  philosophers.  They  who  have 
made  the  most  discoveries  in  science  are 
those  who  have  never  known  Bacon  ;  and 
those  who  have  read  him  and  meditated 
upon  him  have,  like  Bacon  himself,  had 
but  little  success  as  inquirers." 

It  may  be  added  that  no  one  who  has 
any  knowledge  of  the  development  of 
sciences  will  do  otherwise  than  agree  with 
Bernard  as  against  the  popular  writers. 
Indeed,  the  characteristic  trait  of  scientific 
inquiry,  in  whatever  branch,  is,  that  it  is 

192 


HIS   LATER    WRITINGS 

even  in  its  humblest  efforts  "  philosophy/' 
Moreover,  not  only    is    it    v/ell-nigh    im- 
possible to  reach  the  solution  of  even  the 
smallest  scientific  problem  without  finding 
that  it  bears  on  some  truth  greater  than 
itself;    but   it  is  also,  and   even  more  so, 
impossible    to    gain    a    true    insight    into 
larger   scientific    verities   without    a    strict 
and   often   a  prolonged  apprenticeship,  in 
what  to  the  popular  writer  seems  the  hod- 
man's part  of  scientific  inquiry.     Only  by 
letting   the    spirit    which    dwells    in    each 
branch  of  science  soak,  as  it  were,  in  the 
mind  by  repeated  and  almost   daily  con- 
verse with  its  facts  and  simpler  truths,  can 
any  one  hope  to  get  a  real  grasp  of  its 
higher  teachings. 

The  meditations  on  method  to  which 
Bernard  was  thus  led  in  his  enforced 
retirement,  though  they  were  merely  the 
fuller    development    of    what    had    been 

193  o 


CLAUDE    BERNARD 

in  his  mind  from  earlier  days,  made 
themselves  felt  during  the  whole  of  the 
rest  of  his  life.  Even  in  his  earliest 
papers,  short  as  they  often  were,  he  fre- 
quently turned  aside  from  the  narration  of 
an  experiment,  and  the  discussion  of  the 
conclusions  which  might  be  drawn  from 
it,  to  point  a  moral  as  to  the  excellence 
of  this  or  that  method,  and  to  insist  on 
the  criteria  of  the  true  spirit  of  inquiry. 
But  from  this  time  onward  deliverances 
on  method  became,  in  all  his  writings, 
longer  and  more  frequent.  Indeed,  it  may 
almost  be  said  that  the  rest  of  his  life  was 
in  the  main  devoted  to  the  completion  of 
his  earlier  labours,  and  to  an  exposition, 
richly  illustrated  by  instances  new  as  well 
as  old,  of  the  principles  which  ought  to 
guide  the  investigator  into  biologic  pro- 
blems. Though  never  a  year  was  passed, 
though  never  a  course  of  lectures,  or  even 

194 


HIS   LATER   WRITINGS 

a  single  lecture,  was  delivered  without 
his  bringing  to  light  some  new  fact,  or 
placing  some  old  fact  in  a  new  light,  he 
never  again  made  known  results  of  such 
supreme  importance  as  those  which  his 
earlier  labours  had  brought  to  him.  He 
was  led  more  and  more  into  general  views, 
and  the  problems  which  he  attacked  in  his 
lectures  took  on  more  and  more  a  general 
nature. 

These  features  may  be  observed  in  the 
contribution  which  he  made  in  1867  to 
the  "  Recueil  des  Rapports  sur  les  progres 
des  lettres  et  des  sciences  en  France,"  and 
which  was  republished  in  1872  under  the 
title  of  '^  De  la  Physiologie  generale." 
They  may  also  be  seen  in  his  various  later 
lectures.  But  they  are  conspicuous  in  his 
"  Lemons  sur  les  phenomenes  de  la  vie 
communs  aux  animaux  et  aux  vegetaux." 
Indeed,  in  his  later  days  he  became  more 

195 


CLAUDE   BERNARD 

and  more  drawn  towards  those  funda- 
mental properties  of  living  bodies  which 
may  be  observed  alike  in  animals  and  in 
plants. 

In  this  latter  line  of  inquiry  he  was  a 
leader.  Every  inquirer,  it  is  true,  into 
physiological  problems  who,  whether  in 
these  latter  days  or  in  the  old  times,  has 
reached  the  truth  in  some  special  investi- 
gation, has  looked  with  wistful  eyes  at  the 
deeper,  more  general,  questions  which  lie 
below  the  special  ones,  and  which  are, 
as  it  were,  laid  bare  by  the  solution  of  the 
special  problem.  Those  general  questions 
are  such  that  in  discussing  them  the  super- 
ficial differences  between  the  plant  and  the 
animal  seem  of  insignificant  moment. 
To-day,  perhaps,  when  so  many  special 
problems  have  been  successfully  solved, 
men's  minds  are  becoming  more  than  ever 
busied  with  such  general  problems  presented 

196 


HIS   LATER   WRITINGS 

by  all  living  beings,  whether  simple  or 
complex,  whether  called  animals  or  plants. 
And  Bernard,  in  being  drawn  especially 
towards  such  problems,  was  a  pioneer  on  a 
line  of  inquiry  which  is  now  engaging 
many  active  minds,  and  which  seems  likely 
to  be  energetically  pursued,  and  to  bear 
fruit  even  in  the  near  future. 


197 


VlII 

Latter  Years 

IN  the  summer  of  1864,  soon  after  his 
return  with  at  least  temporarily  re- 
stored health  to  active  life  and  the  joys 
of  laboratory  work  he  made  his  first 
acquaintance  with  the  Court.  In  his 
private  life  he  had  ever  shown  a  retiring 
disposition  ;  nothing  could  be  more 
repugnant  to  his  nature  than  any  wish 
to  push  himself  into  the  notice  of  those 
whom  others  might  consider  as  great  and 
influential.  He  had  his  own  idea  of 
what  true  greatness  was  ;  he  knew,  too, 
his  own  worth ;  and  he  only  cared  to  be 

198 


LATTER   YEARS 

thought  well  of  by  those  of  whom  he 
himself  thought  much.  He  felt  honoured 
when  the  great  men  of  mind  praised  him, 
and  counted  it  a  great  thin^  when  the 
Academy  took  him  into  its  select  fold. 
But  he  had  no  desire  for,  and  indeed 
shrank  from,  social  distinctions  and  from 
marks  of  favour  at  the  hands  of  those  in 
high  places.  Had  he  wished  otherwise, 
the  way  would  have  been  easy  for  him. 
With  Duruy,  now  high  in  political  posi- 
tion, he  had  been  familiar  while  the  poli- 
tician was  as  yet  a  humble  professor. 
With  Henry  St.  Claire  Deville,  who  at 
that  time  was  on  terms  of  intimacy  with 
the  Emperor,  he  had  close  personal  relations, 
being  indeed  much  attached  to  him. 
These,  or  others,  could  readily  have 
brought  him  into  the  circles  of  high 
society.  For  a  long  time,  however,  he 
held   aloof.      Not  that   he  had  any  very 

199 


CLAUDE  BERNARD 

strong  political  feelings,  but  he  simply  did 
not  care  for  social  distinctions.  One  day, 
however,  the  Emperor  Louis  Napoleon, 
always  anxi6us  to  secure  the  goodwill  of 
eminent  men  of  science,  invited  Bernard  to 
take  part  in  the  festivities  at  Compiegne. 
Bernard  accepted  and  paid  the  visit  in 
company  with  Pasteur,  who  was  also  one 
of  the  many  invited  guests.  The  Em- 
peror, as  is  well  known,  had  pronounced 
spiritualistic  tendencies ;  and  it  may  be 
readily  imagined  that  when  he  began  to 
talk  with  Bernard  he  found  he  had  come 
across  a  mind  able  to  tell  many  things 
which  were  to  him  of  a  new  and  startling 
nature.  So  fascinated  was  he  with  what 
the  physiologist  had  to  say  concerning  the 
problems  of  life  and  the  proper  attitude  of 
mind  in  which  to  approach  them,  that  the 
talk  instead  of  being  limited  to  a  few 
courtly  remarks  and  polite  rejoinders,  was 

200 


LATTER   YEARS 

prolonged,  to  the  envy  of  others,  into  a 
lively  discussion  of  some  two  hours' 
length,  which  the  Emperor  concluded  by 
saying,  "  You  are  a  great  man  of  science, 
and  I  want  you  to  be  pleased  with  me.'' 
Calling  to  his  side  M.  Duruy,  the  then 
Minister  of  Public  Instruction,  he  said  to 
him,  *-'You  know  M.  Claude  Bernard; 
see  that  he  has  all  that  he  wants." 

A  few  days  afterwards  the  Minister  sent 
for  Bernard,  and  asked  him  what  could 
be  done  for  him.  *'  For  myself,"  said 
Bernard,  ''  I  want  nothing  ;  but  my  science 
is  in  great  want  of  proper  laboratories." 
Up  to  that  time  his  only  laboratory  had 
been  the  one  at  the  College  de  France,  for 
the  chair  which  had  been  created  for  him 
at  the  Sorbonne  carried  with  it  neither 
laboratory  nor  assistant.  As  the  result 
of  the  interview  at  Compiegne  two  well 
installed  laboratories  were  established,  one 

201 


CLAUDE  BERNARD 

at  the  Sorbonne,  the  other  at  the  Museum 
d'Histoire  Naturelle  at  the  Jardin  des 
Plantes,  the  latter  in  connection  with  a 
chair  of  Physiologic  generale,  which  was 
being  instituted  for  him  there,  and  into 
which  he  entered  in  1868,  relinquishing 
the  chair  at  the  Sorbonne  to  his  pupil, 
Paul  Bert. 

Thenceforward  his  life,  though  it  con- 
tinued to  be  one  of  labour,  was  one  of 
well-being  and  honour.  In  1868  he  was 
admitted  into  the  Academic  Fran^aise,  and 
made  one  of  the  ''  Immortals,"  replacing 
Flourens  ;  he  took  his  seat  on  May  29  th 
in  that  year,  pronouncing,  according  to 
custom,  the  Eloge  on  his  predecessor. 

In  1869  the  Emperor  made  him  a 
Member  of  the  Senate ;  but  he  never  took 
his  seat,  and  the  events  of  1870  deprived 
him  of  it.  He  had  conquered  the  Em- 
peror, but  the  Emperor  had  also  conquered 

202 


LATTER    YEARS 

him  ;  and  though  in  earlier  days  he  might 
have  been  considered  as  an  Orleanist,  not 
so  much  from  personal  conviction  as 
because  many  of  his  early  associates  be- 
longed to  that  party,  he  at  this  time  might 
have  reckoned  among  the  Imperialists. 
For  this  reason,  perhaps,  but  also  and 
perhaps  still  more  because  he  felt  no  real 
interest  in  such  things,  he  held  aloof  for 
the  rest  of  his  life  from  politics,  though 
he  became  friends  with  many  of  the  men 
of  the  Republic,  more  especially  with 
Gambetta. 

During  these  latter  days  he  lived  in 
comparative  comfort,  in  adequate  apart- 
ments on  the  first  floor  of  No.  40,  Rue 
des  Ecoles,  just  opposite  the  chief  entrance 
of  the  College  de  France.  He  had  by 
this  time  quite  recovered  from  the  illness 
of  which  we  spoke  in  the  last  chapter. 
Indeed  his  health  had  become  better  than 

203 


CLAUDE   BERNARD 

it  ever  had  been  before  ;  from  being  thin, 
worn,  and  pale,  he  grew  to  be  somewhat 
stout,  and  a  healthy  colour  v/as  to  be  seen 
in  his  cheeks.  He  lived  alone,  for  the 
dissensions  with  his  wife,  to  which  we 
referred  some  time  back,  had  led  to  an 
early  separation,  and  his  two  daughters, 
his  only  children,  were  also  estranged  from 
him.  One  of  these,  who  is,  or  a  short  time 
ago  was,  still  alive,  was  so  far  removed 
from  sympathy  with  her  father's  labours, 
that  she  spent  much  of  the  means  which 
fell  to  her  in  founding  hospitals  for  dogs 
and  cats,  with  the  view  of  atoning  for  what 
she  considered  the  crimes  of  vivisection 
which  her  parent  had  committed.  He  lived 
alone,  attended  by  an  old  servant  maid,  who, 
devoted  to  him,  and  a  skilful  cook,  took 
all  possible  care  of  him,  so  far  at  least  as 
was  consistent  with  the  fervent  performance 
of  her  religious  duties.     When  on  Sunday 

204 


LATTER   YEARS 

afternoons  she  was  away  at  vespers,  he  had 
himself  to  open  the  door  to  any  one  who 
called ;  and,  on  one  occasion,  somewhat 
displeased  at  having  to  do  this,  petulantly 
said  to  his  visitor,  "  It  is  not  for  the  sake 
of '  le  Bon  Dieu '  that  Marie  has  gone  out. 
These  vespers  serve  as  an  opera  to  servant 
maids." 

He  went  very  little  into  society,  visiting 
only  at  a  few  houses,  for  the  hours  which 
he  spared  from  the  laboratory  were  fully 
occupied  with  various  labours.  Besides 
the  two  lectures,  which  at  least  he  gave 
weekly,  he  was  very  constant  in  perform- 
ing his  duties  towards  the  societies  to 
which  he  belonged,  the  Academie  des 
Sciences,  the  Academie  de  Medecine,  and 
the  Societe  de  Biologic. 

Yet  had  he  pleased,  he  might  have  been 
much  sought  for.  He  had  charmed  the 
Emperor,   and   indeed   he   charmed    every 

205 


CLAUDE   BERNARD 

one  who  had  the  good  fortune  to  meet 
him.  Tall  in  stature,  with  a  fine  presence, 
with  a  noble  head,  the  eyes  full  at  once  of 
thought  and  of  kindness,  he  drew  the  look 
of  observers  on  him  wherever  he  appeared. 
As  he  walked  in  the  streets  passers  by 
might  be  heard  to  say,  "  I  wonder  who 
that  is  ;  he  must  be  some  distinguished 
man." 

And  his  talk  was  brilliant,  when  he  was 
moved  to  speak.  Scattered  through  his 
lectures  may  be  found  many  pithy  and 
epigrammatic  sayings ;  and  many  others 
fell  from  him  in  friendly  intercourse. 
When  one  day  he  said  to  Gambetta,  "  It 
is  that  which  we  do  know  which  is  the 
great  hindrance  to  our  learning  that 
which  we  do  not  know" — the  acute 
politician  declared  it  was  even  more  true 
in  politics  than  in  science. 

In    his  later   years  his  closest   personal 
206 


LATTER   YEARS 

friends  were  perhaps  Berthelot,  the  chemist, 
and  Renan,  the  philosopher,  both  his  col- 
leagues at  the   College  de   France  ;    their 
friendship  was   one   of  some  thirty  years' 
length  ;  and  very  often  at  the  close  of  the 
day's   work   the    three    met    in   Bernard's 
laboratory     and    held    together    a    brief, 
but    genial   and   witty   talk,    to   the  great 
delight   of  the   young    assistants   present. 
He  was  also  very  intimate  with  Davaine, 
and  followed  with  great  interest  that  in- 
quirer's first  bacteriological  investigations  ; 
indeed  he  at  a  very  early  epoch  grasped 
the  great  importance  and    significance   of 
microbic  life,  and  he  watched  the  develop- 
ment of  Pasteur's  great  researches  with  an 
attention  and  appreciation  born  of  a  clear 
insight  into  their  surpassing  value. 

In  his  early  days  he  was  much  attached 
to  the  distinguished  physician  and  patho- 
logist, Rayer,  whose  influence  over  him  at 

207 


CLAUDE    BERNARD 

that  time  was  perhaps  second  only  to  that 
of  Magendie,  and  who  was  of  great  help 
to  him  in  his  early  struggles.  Towards 
his  old  master,  Magendie,  his  affectionate 
attitude  v/as  almost  that  of  a  son,  so  soon 
as  he  had  overcome  the  initial  dislike 
which  the  former's  rough  nature  and 
abrupt  manners  had  engendered.  Though 
as  his  own  intellectual  character  grew 
he  could  not  help  seeing  more  and  more 
clearly  Magendie's  failings  as  a  scientific 
inquirer,  he  as  it  were  shut  his  eyes  to 
much  ;  in  many  respects  he  followed  the 
lead  of  his  master  with  almost  the  obedi- 
ence of  a  child.  He  was  especially  in- 
fluenced by  Magendie's  opinion  of  the 
worth  of  various  workers  in  science.  An 
investigator  whom  Magendie  held  in  light 
esteem,  or  denounced  as  a  mistaken  oppo- 
nent, Bernard  made  no  effort  to  draw 
near  to  ;  and  hence  in  early  days  he  kept 

208 


LATTER   YEARS 

aloof  from  many  men,  from  Poiseuille, 
for  instance,  to  know  whom  would  have 
been  of  ofreat  advantag-e  to  him.  Indeed 
it  was  not  until  long  after  Magendie's 
death  that  Bernard  wholly  freed  himself 
from  his  old  master's  influence. 

As  for  his  pupils,  these  simply  worshipped 
him.  Some  great  men  in  spite  of  their 
intellectual  force,  in  spite  also  of  the 
possession  of  a  wholly  upright  and  open 
character  never  succeed  in  gathering  round 
them  a  body  of  young  men,  bound  by  the 
ties  of  personal  attachment.  Such  men 
are  masters  in  their  writings  only,  not  in 
themselves  ;  the  bonds  between  them  and 
their  pupils  are  of  the  incorporeal  intellectual 
kind,  and  have  nothing  of  that  body  which 
is  fed  by  love  of  and  esteem  for  the  man. 
It  was  not  so  with  Bernard.  He  had,  it 
is  true,  pupils  in  all  countries,  pupils  who 
had  never  seen  his  face  and  who  called  him 

209  p 


CLAUDE   BERNARD 

master  only  because  they  knew  the  worth 
of  what  he  had  done.  But  over  and  above 
these  he  had  a  closer  band  of  personal 
pupils,  not  men  of  Paris  or  of  France  only, 
but  of  other  lands  as  well,  who  had  heard 
his  voice,  and  had  watched  his  hand  in  the 
laboratory,  and  who  knew  him  as  a  man 
no  less  than  as  a  scientific  worker.  All 
these  loved,  admired,  and  indeed  venerated 
him,  not  only  for  the  great  things  which 
he  had  done  in  science,  not  only  for  his 
quick  intellect  and  for  the  wide  grasp  of 
his  mind,  but  also,  and  perhaps  no  less, 
for  his  charming  character  and  his  moral 
worth. 

In  1877,  the  last  year  of  his  life,  Bernard 
made  three  contributions  to  the  Societe  de 
Biologie.  One  in  April  was  on  his  old 
theme,  Animal  Heat ;  in  this  he  advanced 
nothing  very  new,  but  dwelt  on  the  topo- 
graphy of  the  temperature  of  the  blood, 

210 


LATTER   YEARS 

and  on  the  view  that  heat  was  produced 
not  in  one  special  seat,  but  in  all  the 
tissues,  in  proportion  to  the  chemical 
changes  of  nutrition  taking  place  in  them. 
Once  more,  also,  and  for  the  last  time,  he 
insisted  on  the  difference  between  thermic 
and  vaso-motor  nerves.  A  second  in  May, 
and  a  third  in  June,  were  both  on  gastric 
juice  ;  thus  in  these  he  again  returned  to 
the  subject  of  his  earliest  researches.  He 
also  contributed  three  papers  to  the 
Academic  des  Sciences  :  one  on  May  7,  a 
second  on  May  28  th,  and  a  third  on 
September  loth,  all  three  dealing  with  the 
old  subject  of  the  glycogenic  function  of 
the  liver.  The  first  is  a  mere  brief  note, 
accompanying  the  presentation  to  the 
Academy  of  his  Lemons  sur  le  Diabete  ; 
in  this  he  remarks  on  the  importance  of 
studying  pathology,  from  a  physiological 
point    of    view.     The   second   and   third 

211 


CLAUDE  BERNARD 

constitute  a  more  elaborate  exposition  of 
his  views  of  the    glycogenic  function  of 
the    liver,    during    life    and    after    death. 
He  maintains  that  the  latter  is  simply  the 
continuation  of  the  former,  and  concludes 
with  the  pregnant  observation  that,  while 
the  mechanism  of  the  production  of  sugar 
out    of   starch    and    out   of  glycogen,  by 
means  of  a  ferment,  is  completely  parallel 
in    animals    and    in    plants,    the    question 
whether  a  like  parallelism  holds  good  with 
regard  to  the  formation  of  starch  and  of 
glycogen,   yet  remains  to  be  seen.     This 
is  a  problem  with  which  he  is  occupied, 
and  he  trusts  before  long  to  have  some- 
thing   to  say  about  it.     That  something, 
alas  !  was  never  said. 

The  last  course  of  lectures  which  he 
delivered  was  one  at  the  College  de 
France  during  the  last  months  of  1877, 
the  subject  chosen  by  him  being  the  tech- 

212 


LATTER   YEARS 

nique  of  physiological  experimentation. 
It  was  an  extended  and  developed 
repetition  of  a  course  which  he  had 
given  years  before,  in  1859-60,  at  the 
same  place.  He  recognised  himself  how 
much  of  his  success  as  an  investigator  had 
been  due  to  his  manual  dexterity.  He 
further  recognised  that  this  was  no 
accidental  condition  ;  on  the  contrary,  he 
saw  that  the  exact  and  vigorous  analysis  of 
physiological  phenomena  was  in  the  highest 
degree  dependent  on  operative  skill.  Two 
things,  he  insisted,  were  needed  for  a 
successful  physiological  experiment :  a  clear 
idea  suggesting  the  experiment,  and  skill 
to  put  the  idea  to  the  adequate  test.  As 
he  said  in  his  "  Introduction  a  Tetude  de 
la  medecine  experimentale "  (p.  8):  **To 
be  worthy  of  the  name,  the  experimentalist 
must  be  at  the  same  time  theoretical  and 
practical.     He  ought,  on  the  one  hand,  to 

213 


CLAUDE   BERNARD 

be  completely  master  of  the  art  of  establish- 
ing the  experimental  facts  which  serve  as  the 
materials  of  science,  and,  on  the  other  hand, 
to  have  a  firm  grasp  of  the  scientific 
principles  which  guide  our  reasoning  in 
the  midst  of  the  widely  varied  results  of 
the  experimental  study  of  natural  pheno- 
mena. You  cannot  separate  these  two 
things,  the  head  and  the  hand.  A  dexte- 
rous hand  without  a  head  to  guide  it  is  a 
blind  tool.  A  head  without  a  hand  to 
realise  its  wishes,  is  an  impotent  nothing." 
In  the  many  lectures  which  he  had  given, 
with  the  exception  of  the  course  just 
referred  to,  and  in  the  numerous  memoirs 
which  he  had  written,  though  he  had  never 
failed  to  give  from  time  to  time  directions 
about  the  hand,  he  had  dwelt  chiefly  on 
the  head  and  its  ideas.  This  last  course 
of  lectures  he  proposed  to  devote  entirely 
to  the    hand.     Nothing    he    felt   was  too 

214 


LATTER   YEARS 

small,  too  humble,  too  insignificant  to 
leave  unnoticed.  He  knew  only  too  well 
that  the  success  of  an  experiment  might 
turn  on  what  seemed  to  be  the  merest 
trifle.  And  he  laid  out  for  himself  the 
task  of  embodying  the  vast  experience 
of  his  life  in  the  fullest  and  minutest 
exposition  of  the  details  of  physiological 
experimentation  as  it  ought  to  be  carried 
out  in  order  to  ensure  the  greatest  result. 
Thus  in  the  course  of  lectures  in  question, 
after  spending  some  time  on  the  exposition 
of  general  considerations,  he  descends  to 
the  lowest  details  of  the  laboratory,  begin- 
ning with  precise  instructions  as  to  the 
handling  of  an  animal  and  as  to  the 
administration  of  anaesthetics  in  prepara- 
tion  for  an   experiment. 

The  course  was  published  after  Bernard's 
death,  under  the  title  of  "Lemons  de 
Physiologic  operatoire."      But,  alas,    only 

215 


CLAUDE   BERNARD 

the  first  five  of  the  lectures  were  revised 
by  Bernard  himself,  the  last  on  his  very 
death-bed. 

Drawn  in  his  latter  days,  as  we  said, 
more  and  more  to  ponder  over  the  funda- 
mental properties  of  living  matter,  his  mind 
dwelling  more  and  more  on  the  phenomena 
which  are  common  to  all  living  things, 
whether  animals  or  plants,  he  could  not 
but  be  led  to  meditate  often  on  the  changes 
in  living  beings  brought  about  by  the 
actions  of  so-called  ferments.  These  he 
had  come  across  in  his  very  earliest  re- 
searches. They  had  been  present  to  him 
in  this  research  or  that,  during  his  whole 
life  ;  and  while  he  had  been  making  France 
famous  by  the  discoveries  on  which  we 
have  dwelt  in  former  chapters,  his  friend 
and  colleague,  the  illustrious  Pasteur,  had 
been  adding  like  increments  to  that  fame 
by  his  researches  on  alcoholic  fermentation. 

216 


LATTER   YEARS 

As  is  well  known,  Pasteur  had  come  to  the 
conclusion  that  while  some  changes,  often 
spoken  of  as  those  of  fermentation,  such 
as  the  conversion  of  starch  into  sugar, 
can  be  carried  out  by  means  of  the 
so-called  soluble,  unorganised  ferments 
or  enzymes,  the  change  of  sugar  into 
alcohol  and  carbonic  dioxide  is  the 
direct  act  of  the  living  yeast  cell,  needs 
the  immediate  intervention  of  a  vital 
factor,  and  is  therefore  by  its  very  nature 
wholly  removed  from  the  category  of  ordi- 
nary chemical  reactions.  As  is  also  well 
known,  he  explained  this  special  vital  action 
involved  in  the  formation  of  alcohol,  as 
a  contrivance  on  the  part  of  the  cell  to 
obtain  for  its  ordinary  processes  of 
nutrition  a  supply  of  oxygen  under  cir- 
cumstances in  which  no  supply  of  free 
oxygen  was  present  in  the  medium  in 
which   it  was  living. 

217 


CLAUDE   BERNARD 

To  Bernard  this  calling  on  the  cell  as 
a  Deus  ex  machind  to  serve  as  an  ex- 
planation of  what  could  not  otherwise  be 
explained,  was  in  flagrant  discord  with  the 
principles  of  biological  inquiry  on  which 
he  had  again  and  again  insisted  ;  and, 
though  his  great  friendship  with  Pasteur 
probably  led  him  to  abstain  from  open 
criticism,  he  seems  to  have  marked  the 
problem  as  one  towards  the  solution  of 
which  experimental  inquiry  might  be 
directed.  In  1876  he  had  said  in  a 
letter  :  "I  have  in  my  head  ideas  which 
I  must  above  all  things  work  out ;  "  and 
this  possibly  was  one. 

At  all  events  during  his  holiday  stay  at 
St.  Julien,  in  the  autumn  of  1877,  he  made 
a  large  number  of  experiments  on  the  fer- 
mentation of  the  juice  of  the  grape.  On 
his  return  to  Paris  he  continued  these 
experiments     in     his     laboratory     during 

218 


LATTER    YEARS 

November    and    December.     But    he   said 
little    about    them,    no    one    had   a    very 
clear   conception   of   what   were   the   ideas 
which   he  was  putting  to   the  test,  and  as 
we    shall    presently    state,    a    fatal    illness 
brought   the   inquiry  to  a  premature  end. 
While  prostrated  on  what  was  to  prove  his 
death-bed,    he   said   one  day   to  his  pupil 
d'Arsonval,  "I  beheve  that  I  have  obtained 
some  results  which  will  put  alcoholic  fer- 
mentation in  a  wholly  new  light ;  but  I  am 
too  tired   and  weak    at    this    moment   to 
explain  them  to  you."     The  strength  and 
clearness  of  mind  needed  for  the  explana- 
tion  never,   alas,   came  back  to  him,  and 
whatever  views  he  might  have  had  went 
down    with    him    into    the    grave.     The 
thought  that  he  was   not  to  live  to  give 
to  the  world  the  full  exposition  and  con- 
vincing proof  of  his  conception  saddened 
his    dying    hours.     "  It    would,"   said  he, 

219 


CLAUDE   BERNARD 

"have  been  grand  to  have  ended  with 
that." 

After  his  death,  when  his  effects  in  the 
cottage  at  St.  Julien  were  being  examined, 
a  number  of  very  rough  and  brief  notes 
were  found  hidden  away,  and  these  seemed 
to  indicate  the  line  on  which  he  had  been 
working.  They  were  certainly  not  in  a 
condition  iit  for  publication  ;  and  it  is 
perhaps  to  be  regretted  that  the  enthu- 
siasm of  his  pupils  led  to  their  appearing 
with  an  explanatory  note  in  the  "  Revue 
Scientifique,"  on  the  ground  that  nothing 
which  the  great  master  had  written,  how- 
ever incomplete  it  might  be,  ought  to  be 
lost. 

The  publication  of  these  notes  gave  pain 
to  Pasteur,  who  saw  that  their  effect  was 
to  destroy  the  theory  on  which  he  had  in- 
sisted so  much  ;  he  could  not  bring  him- 
self to  believe  that  his  old  friend  who  was 

220 


LATTER   YEARS 

always  wont  to  exchange  ideas  with  him 
most  fully  and  freely,  could  have  thus  been 
so  long  working  so  to  speak  against  him, 
without  saying  so  much  as  a  word  of  what 
was  in  his  mind.  And  some  words  on  the 
matter  passed  between  Pasteur  and  Berthelot 
in  the  Academie  des  Sciences. 

It  would  be  unjust  to  lay  any  great 
stress  on  these  rough  notes  of  a  set  of 
experiments  obviously  tentative  and  incom- 
plete, or,  from  abrupt  sentences  written 
down  here  and  there,  to  infer  that  Bernard 
thought  that  he  had  solved  his  problem. 
Still  it  seems  very  clear  that  he  did  think 
that  he  was  at  least  on  the  road  to  the 
proof  that  alcoholic  fermentation  could 
be  carried  out  by  means  of  a  soluble 
ferment,  working  outside  the  cell,  and 
so  apart  from  any  direct  action  of  the 
cell,  a  ferment  capable  of  performing  its 
task    amid    the    free    access     of    oxygen. 

221 


CLAUDE   BERNARD 

Had  he  lived  to  complete  this  inquiry 
of  his,  Bernard  would,  by  some  twenty 
years,  have  anticipated  Buchner,  his  suc- 
cessor in  this  line  of  inquiry  ;  his  very 
last  research,  fragmentary  as  it  was,  was 
a  parting  proof  of  how  far  ahead  the 
light    of  his   genius    threw  its   rays. 

During  November  and  December  of 
1877,  Bernard  was  busy  in  his  laboratory 
at  the  College  de  France,  chiefly  occupied 
with  these  fermentation  experiments  ;  but 
on  the  last  day  of  the  year  he  was 
seized  in  the  laboratory  with  a  chill, 
and  left  it  to  return  to  it  no  more. 
The  chill  marked  the  onset  of  a  grave 
illness,  an  acute  affection  of  the  kidneys. 
After  lingering  for  some  time  he  finally 
passed  away  on  the  loth  of  February, 
1878. 

Even  on  what  was  to  prove  to  be  his 
death-bed    he  could    not    be  wholly  idle. 

222 


LATTER   YEARS 

The  lectures  on  "Physiologie  operatoire,'* 
to  which  we  referred  above,  as  being  deli- 
vered at  the  College  de  France  during 
the  preceding  winter  and  spring,  were 
being  prepared  for  publication  by  his 
pupil,  Mathias  Duval  ;  and  Bernard 
strove  to  the  end  to  give  these  a  final 
revision  before  they  saw  the  light.  But 
only  the  proofs  of  the  first  five  lectures 
thus  felt  the  touch  of  the  master's  dying 
hand  ;  his  strength  then  failed  him,  he 
could  do  no  more.  The  last  words 
which  came  to  the  public  from  him  who 
had  wrested  such  great  truths  from  Nature 
by  experimental  inquiry,  were  words 
devoted  to  counsel  as  to  those  minute 
details  of  the  conduct  of  a  physiological 
experiment,  by  which  the  fruitfulness  or 
barrenness  of  the  experiment  is  so  much 
determined. 

At   his   death   all   Paris   wept.     In  the 
223 


CLAUDE  BERNARD 

Chamber  of  Deputies  the  then  Minister  of 
Public  Instruction,  M.  Bardoux,  proposed 
that  the  great  man  whom  France  had  just 
lost  should  be  laid  in  his  grave  with  all  the 
pomp  and  ceremony  of  a  public  funeral, 
at  the  expense  of  the  State.  Gambetta, 
acting  on  the  occasion  as  the  Reporter  of  the 
Budget  Commission,  supported  the  proposal 
in  a  speech  in  which,  speaking  not  only  as 
an  admirer  but  as  a  friend,  he  dwelt  on  the 
greatness  and  goodness  of  the  man  who  had 
passed  away,  insisting  that,  among  other 
marks  of  an  exalted  mind,  he  possessed 
this  great  one,  that  he  had  never  let  him- 
self be  led  away,  either  by  party  spirit 
or  by  the  dogmas  of  a  school  or  by 
private  feelings.  Up  to  this  time  France 
had  given  such  a  token  of  national  esteem 
to  none  but  princes,  statesmen,  or  soldiers. 
Bernard  was  the  first  man  of  science  or  of 
letters  who  was  thus  laid  to  rest  with  the 

224 


LATTER   YEARS 

display  of  a  great  procession  and  a 
solemn  function  in  the  draped  cathedral  of 
Notre  Dame. 

Dumas,  Vulpian,  P.  Bert,  Moreau,  and 
others  spoke  at  the  grave  in  the  name  of 
the  several  societies  and  institutions  with 
which  Bernard  had  been  connected.  A 
year  later,  in  February,  1879,  Paul  Bert, 
who  followed  Bernard  in  the  chair  at  the 
Sorbonne,  and  was,  perhaps,  his  favourite 
pupil,  delivered  a  discourse  upon  him  in 
a  Conference  at  the  Sorbonne  ;  and  a 
little  later,  in  April,  Renan,  in  succeeding 
Bernard  at  the  Academic  Fran^aise,  pro- 

r 

nounced  his  Eloge. 

In  1886,  a  bronze  statue  was  erected  to 
him  in  the  court  of  the  College  de  France, 
the  seat  of  his  so  many  brilliant  labours  ; 
and  in  1894  another  statue  was  erected  at 
Lyons,  in  the  great  court  of  the  Faculty 
of  Medicine  and  Science. 

225  Q 


IX 

Conclusion 

IN  the  preceding  pages  we  have  at- 
tempted to  show  what  Claude  Ber- 
nard did  for  Physiology,  and  to  indicate, 
in  some  detail,  the  workings  of  his  mind 
by  which  he  was  led  to  lay  hold  of  the 
truths  which  he  lay  bare  to  mankind.  If 
we  go  a  step  further  and  attempt  to  analyse 
his  genius,  if  we  put  to  ourselves  the  ques- 
tion what  were  the  qualities  of  Bernard's 
mind  and  character  (for  the  two  cannot 
be  separated  in  an  investigator),  by  which 
he  stood  above  the  barren  or  even  the 
ordinary    industrious    inquirer,    by    virtue 

226 


CONCLUSION 

of  which  he,  instead  of  groping  long  and 
wearily  in  dimness  if  not  in  darkness,  as  it 
were,  rapidly  or  even  suddenly  diving  into 
the  obscure,  brought  out  the  truth  at  once 
into  light,  we  shall  find  three  conspicuous 
traits.  I  say  nothing  of  his  conscientious 
adherence  to  exact  truth,  of  his  refusing  to 
think  he  saw  that  which  might  be  expected 
to  appear  but  was  not  to  be  seen,  of  his 
never  being  willing  to  look  upon  the 
**  almost "  or  ''  very  near "  as  good  as 
*'  quite."  This  he  had  in  common  with 
many  other  observers  whose  results  have 
nevertheless  been  of  mediocre  value.  And 
without  this  he  too,  in  spite  of  all  else  he 
had,  would  have  been  barren  or  worse. 
But,  over  and  above  this  essential  condition 
of  all  successful  inquiry,  he  had  other  pre- 
rogatives which  are  not  often  found  in  one 
man.,  Of  these  perhaps  the  most  important 
was  an  imagination  ever  on  the  alert.     In 

227 


CLAUDE  BERNARD 

this  respect  he  presented  a  strong  contrast 
to  his  master  Magendie,  whose  way  was 
somewhat  that  of  a  prospector,  prodding 
and  digging  in  all  directions,  in  the  hope 
that  the  precious  ore  of  a  new  truth  might 
at  times'  be  turned  up.  Bernard,  on  the 
contrary,  always  worked  under  the  guidance 
of  some  leading  idea.  "  He,"  said  he,  one 
day,  "  who  does  not  know  what  he  is  looking 
for,  will  not  lay  hold  of  what  he  has  found 
when  he  gets  it."  And  his  fertile  mind  was 
ever  ready  to  supply  him  with  a  clear  idea 
by  which  to  work.  He  has  himself  in  his 
*' Introduction  a  I'etude  de  la  Medecine 
Experimental,"  given  us  an  admirable  de- 
scription of  the  genesis  and  growth  of  a 
successful  experimental  inquiry.  To  the 
observer  brooding  over  the  phenomena 
presenting  themselves  to  him  there  comes 
the  thought  that  if  a  certain  state  of  things 
were  supposed  to  exist,  or  if  a  certain  se- 

228 


CONCLUSION 

quence  of  events  were  supposed  to  take 
place,  the  occurrence  of  the  phenomena 
must  necessarily  follow  ;  and  he  forthwith 
set  about  to  seek  for  evidence  whether  the 
things  so  supposed  do  really  exist  or  no. 
Observation  starts  a  hypothesis,  and  ex- 
periment tests  whether  the  hypothesis  be 
true  or  no.  Such  is  a  research  reduced 
to  its  simplest  terms.  The  experiment 
once  devised  must  be  carried  out  in  ac- 
cordance with  acknowledged  rules  and 
precepts  ;  there  is  little  or  no  scope  here 
for  differences  in  intellectual  power  between 
one  inquirer  and  another.  But  in  the 
origin  of  the  hypothesis  out  of  the 
observation,  and  in  the  framing  of  the 
needed  experiment,  there  is  room  for 
all  the  difference  between  genius  and 
stupidity  or  foolishness.  It  is  in  the 
putting  forth  the  hypothesis  that  the  true 
man  of  science   shows   the  creative  power 

229 


CLAUDE   BERNARD 

which  makes  him  and  the  poet  brothers. 
His  must  be  a  sensitive  soul,  ready  to 
vibrate  to  Nature^s  touches.  Before  the 
dull  eye  of  the  ordinary  mind  facts  pass 
one  after  the  other  in  long  procession,  but 
pass  without  effect,  awakening  nothing.  In 
the  eye  of  a  man  of  genius,  be  he  poet  or 
man  of  science,  the  same  facts  light  up  an 
illumination,  in  the  one  of  beauty,  in  the 
other  of  truth ;  each  possesses  a  responsive 
imagination.  Such  had  Bernard,  and  the 
responses  which  in  his  youth  found  expres- 
sion in  verses,  in  his  maturer  and  trained 
mind  took  on  the  form  of  scientific  hypo- 
theses. 

An  hypothesis  may  be  good  or  may  be 
bad,  may  be  fruitful  or  may  be  barren. 
This  may,  on  the  one  hand,  depend  on  the 
very  nature  of  the  hypothesis,  which  may, 
even  at  the  outset,  in  its  very  origin, 
be  worthless  and  wrong.      On  the  other 

230 


CONCLUSION 

hand,  failure  or  success  may  depend  on 
the  framing  of  the  experiment  by  which 
the  hypothesis  is  tested.  Here,  too,  the 
imagination  comes  into  play.  The  man 
who  constructs  a  hypothesis  without 
supplying  an  adequate  programme  for  its 
trial  by  experiment,  is  a  burden  to  science 
and  to  the  world ;  and  he  who  puts  forward 
hypotheses,  which  by  their  very  nature  can 
not  be  so  tried,  is  worse,  for  he  is  a  purveyor 
of  rubbish.  We  can  never  know  what 
rejected  ideas  passed  through  Bernard's 
mind,  ideas  rejected  so  soon  as  born,  because 
they  were  unfitted  for  trial  ;  probably  to 
his  as  to  other  like  fertile  minds,  there 
came  many  thoughts  which  he  buried  at 
their  birth,  letting  live  only  those  which 
seemed  to  him  of  promise.  But  this  we 
may  say  that  the  force  of  his  imagination 
was  as  conspicuous  in  the  framing  of  ex- 
periments to  test  his  views  as  in  the  quick- 

231 


CLAUDE   BERNARD 

ness  with  which  new  views  sprang  up  in 
.his  mind. 

In  the  framing  of  experiments  but  not 
in  the  carrying  of  them  out.  In  this  we 
may  recognise  a  salient  difference  between 
the  foolish  and  the  wise  investigator, 
between  the  false  scientaster  and  the  true 
inquirer.  In  the  case  of  the  former, 
imagination,  even  though,  as  sometimes 
happens,  it  may  have  been  dull  and  sluggish 
in  building  up  the  hypothesis  and  planning 
the  experiment,  awakens  into  riotous  activity 
while  the  experiment  is  going  on  ;  it  sees 
visions  and  dreams  dreams  ;  it  sees  in  the 
results  of  the  experiment  things  which 
never  were,  is  blind  to  things  which  stare 
it  in  the  face,  and  comes  away  with  a 
distorted  and  lying  picture  of  what  has 
taken  place.  In  the  case  of  the  latter, 
imagination,  knowino^  that  its  work  is 
done    so   soon  as  the  experiment  begins, 

232 


CONCLUSION 

stands  aloof  during  the  whole  time  that 
it  is  going  on,  making  way  for  calm,- 
frigid  observation  which,  in  its  perfect 
action,  while  it  lets  nothing  escape  it,  sees 
nothing  but  what  really  is.  Such  was 
Bernard's  way  when  he  came  to  the  experi- 
ment which  his  imaginings  had  prompted. 
Active  before  and  after  the  experiment, 
during  the  experiment  itself  his  imagination 
was,  as  it  were,  dead. 

Another  conspicuous  trait  of  Bernard, 
on  which  we  have  already  dwelt,  also 
the  product  of  his  quick  imagination,  was 
the  readiness  with  which  he  turned  aside 
from  an  inquiry  on  which  he  was  already 
engaged,  to  follow  out  a  new  line  of 
inquiry  suggested  by  some  intercurrent 
fact.  To  divine  when  thus  to  turn  aside 
and  when  not  to  turn  aside  but  to  go 
straight  on,  regardless  of  side  issues  how- 
ever tempting,  is  perhaps  the  chiefest  sign 

233 


CLAUDE   BERNARD 

of  genius  in  inquiry.  The  man  who, 
refusing  to  take  heed  of  any  beckoning  by 
the  way,  plods  doggedly  on  along  the  path 
which  he  has  marked  out  for  himself,  may 
miss  a  golden  opportunity.  On  the  other 
hand,  the  man  who  is  always  ready  to 
leave  the  main  track  in  order  to  follow 
out  the  bye-paths,  which  in  almost  every 
inquiry  open  out  from  time  to  time  on 
either  hand,  runs  the  risk  of  losing  his 
way  in  blind  alleys  and  of  coming  late  to 
his  real  goal,  or  it  may  be  never  reaching  it 
at  all.  Bernard,  in  nearly  every  one  of 
his  inquiries,  was  led  to  turn  aside  from 
the  road  which,  at  starting,  he  had  marked 
out  for  himself;  his  instinct  guided  him 
to  leave  the  road  at  the  right  turning, 
and  to  follow  a  bye-path  which  brought 
him   to  a  great  result. 

Lastly,  Bernard's  success  was  in  no  little 
measure    due    to    his   remarkable    manual 

234 


CONCLUSION 

dexterity.  His  hand  was  promptly  obedient 
to  his  mind.  His  facility  enabled  him  to 
put  sharply  and  clearly  the  question  which 
an  experiment  embodied  ;  and  hence  the 
answer  came  to  him  sharp  and  clear.  His 
old  pupils  still  speak  with  admiration  of 
the  almost  marvellous  celerity  and  direct- 
ness with  which  he  would  perform  a  most 
intricate  and  difficult  operative  experiment. 
Without  haste  and  without  hesitation, 
taking  step  after  step  swiftly  and  in  due 
order,  he  would  with  exact  strokes  lay  bare 
and  isolate  a  delicate  structure  by  disentang- 
ling it,  with  the  utmost  neatness,  from  its 
perplexing  surroundings,  and  would  com- 
plete a  difficult  operation  in  time  needed 
by  others  for  mere  preliminary  preparation. 
It  is  told  of  him  that  sometimes,  urged 
by  the  pressing  need  to  get  an  immediate 
answer  to  some  question  with  which  his 
mind  was  stirred,  he  would  come  suddenly 

235 


CLAUDE   BERNARD 

into  the  laboratory,  call  for  an  animal, 
and  then  and  there,  without  so  much  as 
removing  his  hat,  perform  an  experiment, 
it  may  be,  of  no  little  difficulty.  A  false 
worship  of  intellectual  supremacy  has  led 
some  to  ignore'  the  value  of  bodily 
attributes  as  aids  in  the  pursuit  of  truth, 
and  as  elements  in  the  composition  of 
genius  ;  and  indeed  in  some  branches  of 
learning  a  failing  eyesight  and  a  clumsy 
hand  do  not  present  themselves  as  serious 
obstacles  to  success  in  reaching  the  inner 
secrets  of  the  nature  of  things.  In  experi- 
mental science  it  is  otherv/ise.  Here  great 
truths  are  for  the  most  part  come  to  by 
treading  a  flight  of  steps,  each  step  an 
experiment  resting  on  the  one  below,  and 
leading  to  the  one  above.  If  any  one  step 
goes  wrong  the  whole  ascent  is  stopped  ; 
and  the  experiment  will  go  wrong  if  there 
be   bungling   in    the  execution    of    it,    if 

236 


CONCLUSION 

the  details,  even  the  minutest  ones,  fail  to 
be  deftly  carried  out.     The  clumsy  experi- 
menter may  count  himself  fortunate  if  his 
clumsiness  only  leads  to  loss   of  time,  if, 
through  lack  of  the  needed  dexterity,  he 
simply    fails  to  carry  out  the  experiment 
exactly  as  he  wished,  and  therefore  has  to 
try    it    all   over  again.     The   much   more 
common    occurrence   is    that  the  want   of 
skill  mars  the  experiment,  by  introducing 
something,    which    enters    unnoticed    into 
the  result  and  leads,  without  the  experi- 
menter being  aware  of  it,  to  a  wrong  or 
imperfect  answer  being  given  to  the  ques- 
tion   asked.     A    clumsy  experiment  is  in 
most  cases  a  bad  experiment,  leading  to  a 
wrong  conclusion  ;  and  the  evil  which  the 
clumsiness  thus  entails  is  all   the  greater, 
the  more  acute  and  the  more  active  the  mind 
which  is  guiding  the  clumsy  hand.     Hence 
it  comes  about  that  in  experimental  science 

237 


CLAUDE  BERNARD 

skilfulness  of  the  hand,  no  less  than 
quickness  of  the  mind,  must  be  counted 
among  the  attributes  the  possession  of 
which  gives  a  man  the  power  to  pierce 
swiftly  and  surely  into  the  secrets  of 
nature,  the  power  which  his  fellow  men 
seeing  in  him,  speak  of  him  as  having 
genius.  Such  a  skilled  hand  had  Claude 
Bernard. 


238 


INDEX 


Academie  des  Sciences, 
57,64,  74,  84,  94,95, 
108,  no,  114,  120, 
141,  143,  150,  211 

Alcoholic  fermentation, 
experiments  on,  219 

Animal  heat,  influence  of 
the  nervous  system  on, 

105 
"Arthur    de    Bretagne," 

historic  drama,  8 


B 

Barreswil,  48,  72,  74 

Bell,  Charles,  38 

Bernard,  Claude  :  birth, 
I  ;  childhood,  3  ;  Jesuit 
College  atVillefranche, 
4  ;  student  at  Lyons, 
4  ;  pharmaceutical  as- 
sistant   at    Lyons,    5  ; 


literary        aspirations, 
6  ;    writes    vaudeville 
comedy,     7  ;      v^rites 
prose  drama,  7  ;  starts 
for  Paris,  8  ;  "  Arthur 
de  Bretagne,"  8  ;   St. 
Marc  Girardin  advises 
him  to  study  medicine, 
9  ;  medical  studies,  9 ; 
life    in    the    Ouartier 
Latin,  10;  first  experi- 
ments on  livinganimals, 
13  ;  opens   an  experi- 
mental laboratory,  1 3  ; 
appointed     interne    to 
Magendie,  16  ;  official 
preparateur      at       the 
College     de     France, 
21  ;   beginning  of  his 
career    as    a   physiolo- 
gist, 21  ;  strikes  out  a 
path  for  himself,  41  ; 
delivers  private  courses 


239 


INDEX 


of  lectures,  43  ;  publi- 
cation of  first  com- 
munication on  chorda 
tympani,  44 ;  dexterity 
in  dissection,  45,  234; 
thesis  for  the  degree  of 
doctor  of  medicine, 
45  ;  experiments  on 
gastric  juice,  46  ; 
investigations  on  the 
spinal  accessory  nerve, 
48  ;  *'  Concours  pour 
I'agregation,"  48  ;  re- 
searches on  the  pro- 
perties of  the  pancreas, 
50  ;  awarded  the  prize 
of  Experimental  Physi- 
ology, 57  ;  researches 
on  "  recurrent  sensi- 
bility," 58  ;  researches 
on  the  production  of 
sugar  in  the  body,  66 ; 
the  liver  and  the  pro- 
duction of  sugar,  71, 
84  ;  thesis  for  docto- 
rate in  Science,  76 ; 
discovers  that  punc- 
ture of  the  fourth 
ventricle  causes  tem- 
porary diabetes,  j6  ; 
Glycogen,  85  ;  "In- 
ternal Secretion,"  91  ; 


"  Bernard's  granules," 
94  ;  further  papers  on 
glycogen,  95  ;  "  Le- 
90ns  sur  le  Diabete," 
96  ;  discovery  of  the 
vaso-motor  system, 
100  ;  influence  of  the 
nervous  system  on 
animal  heat,  105  ; 
division  of  the  sym- 
pathetic nerve,  106  ; 
researches  on  glandu- 
lar secretion,  120  ; 
"Le9ons  sur  la  chaleur 
animale,"  125  ;  vivi- 
sectional  experiment, 
1 3 1  ;  work  on  inhibi- 
tion, 137  ;  study  of 
poisons,  139  ;  curare, 
140  ;  carbonic  mon- 
oxide gas,  149;  spon- 
taneous generation 
controversy,  158  ; 
difficulties  of  his 
early  surroundings, 
161  ;  escape  of  dog 
with  cannula  and  en- 
counter with  police 
commissioner,  165  ; 
appointed  Magendie's 
deputy  at  the  College 
de    France,   169  ;  un- 


240 


INDEX 


satisfactory  domestic 
relations,  170  ;  first 
lectureasDeputy,  171 ; 
appointed  to  the  new 
chair  of  general  physi- 
ology, 173  ;  elected 
into  the  Academy  of 
Medicine  and  Surgery, 
173  ;  appointed  full 
Professor  at  the  Col- 
lege de  France,  173  ; 
his  enormous  activity, 

173  ;       his      lectures, 

174  ;  publication  of 
"  Lemons  de  physi- 
ologic experimentale," 

177  ;  "Lemons  sur  les 
effets  des  substances 
toxiques  et  medica- 
menteuses,"  177  ; 
"  Lemons  sur  la  physi- 
ologie  et  la  pathologic 
du  systeme  nerveux," 

178  ;  "  Le9ons  sur  les 
proprietes  physiolo- 
giques  et  les  altera- 
tions pathologiques  des 
liquides  de  I'orga- 
nisme,"  178  ;  his  later 
writings,  179  ;  a  break 
in  his  work,  181  ;  his 
state   of  health,    181  : 


retires  to  the  country, 
182;  "experimental 
medicine,"  184;  views 
on  philosophers  and 
men  of  science,  190  ; 
his  first  acquaintance 
with  the  Court,  198  ; 
is  invited  to  Com- 
piegne,  200  ;  asks  for 
new  laboratories,  201  ; 
is  admitted  to  the 
Academic  Fran9aise, 
202  ;  created  Senator, 
202  ;  chair  of  Natural 
History  at  the  Jardin 
des  Plantes,  202  ;  re- 
linquishes chair  at  Sor- 
bonne  to  Paul  Bert, 
202  ;  his  attitude  in 
regard  to  politics,  203  ; 
his  daughters,  204  ; 
personal  appearance, 
206  ;  conversation, 
206  ;  personal  friends, 
206  ;  influence  of 
Magendie  on  him, 
208  ;  worshipped  by 
his  pupils,  209  ;  contri- 
butions to  the  Societe 
de  Biologie,  210  ;  last 
course  of  lectures,  212; 
the    qualities     of    an 


241 


INDEX 


experimentalist,  213  ; 
"  Lemons  de  physi- 
ologie  operatoire,  215  ; 
holiday  at   St.   Julien, 

218  ;  experiments  on 
fermentation  of  grape 
juice,  218  ;  views  on 
alcoholic  fermentation, 

219  ;  last  illness  and 
death,  222  ;  mourned 
by  all  Paris,  223  ; 
public  funeral,  224  ; 
bronze  statue  erected 
at  College  de  France, 
225;  another  statue  at 
Lyons,  225  ;  analysis 
of  his  genius,  226  ; 
his  methods  of  re- 
search, 228  ;  value  of 
the  skilled  hand  in 
experimental  science, 
236 

"  Bernard's  granules,"  94 

Berthelot,  18,  208 

Bidder,  26 

Bichat,  31 

Blondlot    and     artificial 

gastric  fistula,   55 
Bois,  Jacques  du,  17 
Boussingault,  64 
Bowman,  William,  29 
Brachet,  1 10 


Brown-Sequard  and  sec- 
tion of  the  cervical 
part  of  the  sympathe- 
tic, 112 

Budge,  no,  115 


Carbonic  monoxide  gas, 
analysis  of,  149 

Cervical  sympathetic,  ex- 
periments on.  III 

Chorda  tympani,  paper 
on,  44 

College  de    France,    16, 

44.     117,     143.     169, 

173,    174,    177,    178, 

212 
Curare  an  arrow  poison, 

140 
Cuvier,  18,  31 

D 

Dextrose,  68 

Diabetes,  researches  on, 
6']  ;  lectures  on,  97 

Dieffenbach,  166 

Doctorate  in  Science, 
thesis  for,  ']6 

Drama,  Bernard's  his- 
toric, 8 

Dumas,  64 

Dupuy,  no 


242 


INDEX 


E 

Experimental    medicine, 
184 


Facial  paralysis,  reference 
to,  47 

Fattening  of  cattle,  re- 
searches of  Dumas, 
Boussingault,  and 
Payen  on,  64 

Ferrous  sulphate  and 
potassium  ferrocyan- 
ide,  simultaneous  in- 
jection of,  46 

Flourens,  36 

Fontana,  30 


Gastric  juice,  thesis  on, 

45 
Germany,  dominant  spirit 

of  physiological  inquiry 

in,  27 

Girardin,  Saint-Marc,  8, 

9 

Glandular  secretion,  1 20 

Glycogen,  61,  85 
Gmelin,  53 
Goodsir,  John,  29 


Grape  juice,  experiments 
of  fermentation  of, 
218 

Guidi,  Guido,  17 

Gundlach,  experiments 
by,   64 

H 

Henle,  26,  104 
Hensen  isolates  glycogen, 

85 
Hoppe    (Hoppe-Seyler), 

spectroscopic  observa- 
tions on  absorption  of 
oxygen  by  the  blood, 

154 


Imagination,  value  of,  in 
experimental  research, 
80 

"  Internal  secretion,"  91 

K 

Kolliker,  105,  147 

Kiihne,  Willie,  micro- 
scopical search  after 
glycogen,  93 

L 

Laennec,  19 
Lavoisier,  151 


243 


INDEX 


Lehmann,  8i 
Liebig,  27,  64 
Liver  and  sugar  produc- 
tion, 71 
Longet,  36 
Ludwig,  120 

M 

Magendie,    16,    36,    58, 

171,  172,  173 
Magnus,  152 
Marshall  Hall,  28 
Matteuci,  30 
Meyer,  L.,  153 
Miiller,     Johannes,     23, 

102 

N 

Nerves,  vaso-motor,  dis- 
covery of,  100 

Nervous  system,  influ- 
ence of,  on  animal 
heat,   105 


Pancreatic      juice,      in- 
quiries into  action  of, 

55 
Payen,  64 

Pelouze,  166 

Petit,  Pourfour  de,  109 


Philosophers  and  men  of 
science,  190 

Physiological  science 
before   Bernard,   22 

Physiology  at  outset  of 
Bernard's  career,  in 
Germany,  22  ;  in 
England,  28  ;  in  Italy, 
29  ;  in  France,  30 

Poisons,  experiments 
with,   140 

Potassium  ferrocyanide 
and  ferrous  sulphate, 
simultaneous  injection 
of,  47 

s 

Quartier  Latin,  lite  in, 
10 

R 

"  Recurrent  sensibility," 

Reid,  John,  researches  on 
the  cranial  nerve,  28  ; 
on  the  vaso-motor 
nerve,   no 

"  Rose  du  Rh&nc,"  7 


Schwann,  Theodore,  26 
Sharpey,  Professor,  28 


244 


INDEX 


Soci^te  de  Biologic,  52, 
76,85,  107,  115,  121, 
138,  141,  210 

Philomathique,  52, 

59 

Spallanzani,  30 

Spontaneous  generation, 
158 

Stokes,  spectroscopic 
observations  on  the 
absorption  of  oxygen 
by   the  blood,    154. 

Sugar,  researches  on  the 
physiology  of,  66 

Sylvius,  Jacobus,  18 


Tiedemann,  26,  53 


V 

Vagus  nerve,  experiments 

on,  137 
Valentin  and  the  action 

of     pancreatic     juice, 

54 

Vaso-motor   nerves,   dis- 
covery of,  100 

Vidius,  Vidus  17 

Vierordt,  26 

"  Vitalism,"  96 

Volkmann,  26 


W 

Waller,  110,  114 
Weber,  E.  H.,  26 


245 


UNWIN  BROTHERS, 
WOKING  AND  LONDON. 


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